Bernard Susser’s introductory essay:
The behaviorist’s commitment to "methodological individualism" involved them in a problematic relation with such holistic notion as "the state," "society" and the "nation." These deceptively familiar terms, behavioralists claimed, could easily become sloppy and unthinking shorthands; that is, they could lead us to forget that they really stood for specific individuals involved in discrete events. It was among the most pressing of behavioral priorities to puncture "holistic mystifications" such as these and reveal the concrete and particular realities for which they stood. Unless "the state" and "society" were understood as meaning no more than the sum of their parts, they were dubious, if not downright misleading, terms. Empirical research was, in fact, the most effective antidote to these broad abstractions since it limited the investigator to observable phenomena, and these were invariably individual and concrete.
This quest for "hard data" was the behavioralist's consuming passion. And yet it created a novel theoretical challenge unknown to political theorists of the past. If specific occurrences and concrete individuals were all that science could legitimately investigate, how could the mass of accumulated data be organized into an intelligible whole? How could a theoretical framework be constructed that would be sufficiently substantial and credible to integrate the mass of data that poured in, while remaining loyal to behavioralism's strictures against regarding "wholes" as real? How could a movement that rigorously restricted itself to the empirical and concrete generate overall meaning and significance? Could data become coherent and compelling without the introduction of unifying frameworks--frameworks that came perilously near the tabooed idea of "totality"? And, finally, where could these organizing frameworks possibly come from if all genuine scientific knowledge was of an empirical kind?
At first glance, answering these questions seems akin to squaring the circle. On the one hand, a theoretical construct that could translate the scattered bricks of data into a livable, ,,lifted edifice would have to stray from the strict empiricism that behavoralism enjoined. On the other hand, a consistent commitment to the concrete and specific courted the danger of atomistic confusion.
This, of course, is not to say that t.. behavioralists refused to indulge in generalization and abstraction. No intelligible discourse on social behavior can remain at the level of factsheets, brute data, or simple reportage.

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Without generalization there is no meaning, no illumination, no understanding. At stake in the behavioral position was, therefore, not the inevitability of abstractions per se but rather the cognitive stalls to be accorded them. Were these abstractions merely linguistic shortcuts, manners of speaking, kinds of unavoidable fictions that treated individuals as if they were more than individuals? To be sure, behavioralists sometimes spoke as if this was the case. But there was more than a hint of hesitation in their words. After all, the intelligibility and significance they sought in their research seemed to adhere to the generalizations they made rather than to the individual facts they gathered. There seemed to be no exit.
The theoretical challenge was more daunting still because, as opposed to the "grand theories" of classical political philosophy that unashamedly interpreted and appraised public life, this new breed of theories was strictly forbidden, by the first and most uncompromising of behavioral commandments, to indulge in such explicit evaluative activity. Value statements lacked an observable, empirical base and were hence to be rigorously avoided by political scientists who cared for their scientific credentials. What was needed was sometimes called an "empirical theory," but was this not a contradiction in terms? If it was theoretical, in what sense could it be empirical--and vice versa? Without an interpreting perspective, how was one to make sense of what one saw? Could the hard data by itself, without any forbidden nonempirical additions, ever add tip to a meaningful and coherent picture? What would a theory look like that was simultaneously value-free, ideologically neutral, intellectually credible, effective for research, and coherence-contributing?
The most interesting attempts to deal with this conundrum have concentrated on the concept of a system. David Easton's work in this regard series of books that culminated in A Systems Analysis of Political Life he explored the possibilities of viewing political life in systematic terms. Because his work represents probably the clearest and least complex of all "input-output" (as systems analysis is sometimes called) frameworks, it is the best place to start.
What special attributes does the concept "system" have that recommend it to the behaviorally oriented theorist? First of all, system is a "totality'' simulating concept. If thc term system" is understood to mean a persistent co-variance, a substantial degree of coherence, endurance, and interdependence between a complex of units, we appear to be having our cake and eating it too. Without violating the prohibitions against "wholes" that "methodological imposes," systems nevertheless act very much like integrated realities. They cohere without their constituent parts losing their individuality. We can speak of a political system "as if" it was an integral unity while being fully cognizant that it is, in truth, only a series of individual units interrelating. Systems are not "real" or "essential," Easton cautious his readers, they are no more

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than artificial constructions with heuristic value. Indeed, the concept of a system is the farthest behavioralists can go in the direction of "wholes" without trespassing into forbidden scientific terrain.
Systems are, moreover, value-neutral and ideologically indeterminate. They have no appraising content, nor do they appear to add an interpretive dimension to the processed data. Viewing political life in systemic terms organizes our findings around a single focus: the co-variance and interdependence of the units that make up the system. Systems theory postulates axiomatically that changes in one element win not be limited to that unit alone; there is a presumption that they win influence other proximate elements in the system. Systems involve regular patterns holding between constituent elements; a weakening of police surveillance, for example, can be expected to have certain specifiable consequences for crime levels. When a political system fails, therefore, what is involved has nothing to do with some vital essence being slain; it means nothing more than that the individual units involved cease to be interdependent.
We seem then to have the answer to our conundrum: the concept of a system lends coherence to a complex reality without violating empirical individuality; it organizes data without interpreting or appraising it; its axiomatic assumption of interdependence appears to be eminently reasonable, and it holds out the promise of effectively ordering research and categorizing findings. Understandably, therefore, the idea of political life as a cohering system of interdependent units has been a favorite image of behavioral political science. As we shall see below, it has been given: a number of different treatments, each with its own unique variation on the general theme. Moreover, the terminology associated with systems analysis has become so pervasive that it is off-handedly used by many who ,no longer recognize its source.
But how are we to identify specifically political systems from the many other systems into which human behavior is organized? To distinguish political activity from all the rest, Easton proposes a definition of the "political" that has become standard to the point of cliché: politics, he tells us, involves "the authoritative allocation of social values." Because social  values or resources are invariably in short supply (it is impossible, barring  messianic categories, to envisage a reality in which everyone could have everything they wanted whenever they wanted it), a mechanism for their distribution is mandatory.''
 Social values range from the familiar material kind to those possessing the most spiritual qualities. They run the gamut from budgetary allocations to the apportionment of prestige and honor to definitions of what1 is to be counted good. Politics is the struggle between individuals and groups for dominion over these social values. Because in even the most egalitarian design for a theater someone will be privileged  to sit fifth row  center while someone else will need to sit in the balcony, a criterion for seat allotment cannot be avoided. Should the better seat be given to the one who is wining to pay more money for it, should it perhaps be

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allocated by a system of rotation or lottery or first-come-first-serve, maybe according to aristocratic lineage, according to religious status, by gender, by rank within the party, government or army, etc.? (Each of these criteria have, in fact, been utilized by different political systems at one time or another.)
Politics organizes collective decisions such as these and announces the victors and the vanquished. And because human interests are often as incompatible as they are highly charged, these distributions cannot be voluntary. Politics is a world in which there must be a last word and it must be binding. To speak of a political system, therefore, is to distinguish activity that is directed to the "authoritative allocation of social values" from other systems of human activity (for example, the economic system) that revolve around a different axis.
A distinction between the political and the economic systems does not mean to imply that any kind of real border exists between them in actual public life. Easton's distinction is purely conventional; it aims only at demarcating systems for the purpose of study. In practice, no such system is autonomous or closed. They interpenetrate so thoroughly as to be inextricable. In fact, each system receives most of its inputs from other neighboring systems while passing most of its outputs on to them as well. Taxation policy, for example, clearly appertains to the economic system. The various interests that compete to determine the nature of the tax structure (although they originate within the economic system) converge on the political system in search of a favorable resolution to the issue. When an authoritative political determination has been made, taxation policy--the political system's output-now reenters the economic system : as all economic input. All of  which is only to say that the commerce across system lines is both rich in itself and, moreover, imperative in order for each system to survive. · There is little point in fleshing ,out in detail the many elements that go into constituting a political system; Easton's essay is clear, enlightening, and self-explanatory. It will be sufficient for us to briefly develop some of the more significant themes that are involved. It is recommended at this point that the reader turn to Easton's essay. The discussion below is best read afterwards because it assures some familiarity with the ideas ' that Easton presents.
Inputs, Easton asserts, are comprised of demands and supports. Demands on a political system come in a virtually infinite variety of forms: from demands for financial support, to demands for services, to demands for the enforcement of certain moral principles, to demands for symbolic recognition. Demands drive the motor of politics, and politics operates to convert demands into authoritative policy outputs.
Unregulated demands spell the doom of a political system. Were these protean demands to come pouring into a political system unselectively it would very rapidly suffer from flooding, overload, and breakdown. (By

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contrast, when demands, for whatever reason, do not reach thc political process, system "starvation" is said to occur. Although it is less prevalent than overload, it is no less fatal). "Systems maintenance" requires that demand processing be kept to a manageable level. To accomplish this end, all political systems establish filtering devices that select and limit the demands that actually enter the determining stages of the political process. Institutional, cultural, and structural "gatekeepers" of various kinds guard the entrance to the "conversion process." They disqualify those demands that do not conform to very severe specifications of importance, consensuality, feasibility etc.
Where political systems are simple, the demands they generate as well as the institutions that deal with these demands tend to be commensurately simple. With the introduction of complexity into a political community--and complexity is an invariable concomitant of modernization--the need for a more structurally differentiated processing mechanism becomes vital. For the vast quantities of demands that characterize modern states to be expeditiously processed requires a degree of specialization and institutional differentiation provided only by a diversified bureaucratic structure.
Were demands the only input, political systems could not long survive. Alongside demands, political systems require what Easton calls "supports." For the system's arbitration between competing demands to be acceptable and definitive, supports must underwrite the mechanism of choice. Supports may be based on cultural, ideological, or national loyalties. They may also rest on coercion, fear, and the lack of available alternatives. Whatever their source, supports provide effective criteria-one might speak of them as natural gatekeepers--for the selection process between demands. Those that are deemed "inappropriate" to the system are disqualified before they get very far. In addition, supports validate and fortify the rules of the decision process. And finally, they authorize the binding nature of the system's outputs.
Political systems, therefore, are the totality of the process iii which inputs are converted into outputs. The actual conversion of input to output is effected by the various governmental institutions expressly designed for these ends. These are the cauldrons of politics into which the prepared input material is poured and out of which issues the finished output product. (Parenthetically, it is typical of the behavioral distaste for institutional analysis that Easton speaks almost not at all of actual organizations that effect the conversion. They are for him a "black box" into which inputs stream and out of which outputs emerge.)
This, however, is hardly the end of the process. Outputs need to travel full-circle and return, via the feedback loop, to the input side of the conversion process. Outputs that are deemed satisfactory by major elements within the system generate renewed supports and put to rest the original demands that set the conversion process into motion. Out-puts that are judged inadequate may well erode supports and dangerously

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intensify the level of demands. The interdependence and co-variance of the various units that make up a system are nowhere more clearly visible than here. In a sense, tire political system has a kind of reflexive self-consciousness that is sensitive to its own activity. It regularly monitors its own pulse and responds to its own malfunctioning by attempting to restore a dynamic balance. When the system goes somewhat askew--as, for example, when certain significant demands are consistently unfulfilled--the pressure mounts for a corrective operation to restore system equilibrium. The feedback loop, the system's responding to itself, endows it with a form of intelligence. Indeed, man) commentators have seen in Easton's systems what can almost be called a win to restore its own stability. It is here, when tire system acts as an almost sentient unit, that the behavioralist comes closest to violating his own prohibition against ascribing to many concrete individuals the character of a whole.
Critiques of systems analysis have come from many quarters, two of which stand out as broadly typical. The first argues that Easton's notion of a political system is too transparently axiomatic to be of real use. The second contends that despite its protestations of value-neutrality, Easton's system betrays clear signs of the politically liberal intellectual context in which it had its origins. Let us take up these critiques by turns.
For all its appealing simplicity and clarity, many have observed that Easton's brand of "input-output" analysis figures very little in actual research; it is more contemplated than worked with. Although it represents a striking example of what political theorizing in the modernist key would entail--clean cold lines of glass and steel rather than the warmly idiosyncratic and baroque shape of classical thought--the theory fails to accomplish its declared purpose of providing a serviceable template for research. Where it has been used, its contribution turns out to be more terminological than real. Easton's system is, its detractors claim, a heuristic model possessing a 13nrely deductive and axiomatic quality rather than a tool which aids the investigator in the field. Easton's model of the political system, they claim, is far too generic and tautological to be useful. In other words, it is a restatement of the essential elements in the political process stripped bare of any and all specific characteristics, a minimalistic conceptualization that gains clarity at the price of abstraction.
To put Easton's concepts into operation would require specifying which concrete demands and supports are typical of a particular system. The bare categories "demands" and "supports," of course, tell us nothing, so a firm grasp of the sociological, economic, cultural, ideological, and religious attributes of the system being studied is required. And : because demands and supports (even if they are fleshed out with the aforementioned attributes) cannot be adequately studied in a dimensionless present, using Easton's concepts would also require exploring the

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system's past, its development, and its distinctive historical sensitivities and strengths. Moreover, since a system's inputs and outputs derive from and issue into neighboring systems, the study of a political system would require careful attention to the many other systems that form its natural environment.
Without all this, it would be impossible to distinguish between the significant and the trivial concerns of a system, between its episodic and enduring issues. Lacking knowledge of a system's historical and cultural peculiarities would make it impracticable to compare the system either to itself (in other periods) or to others. It would be difficult to discriminate between crisis situations and normal ones, between weakening supports and mere verbal bravado, between marginal and mainstream demands, and so on. But if it is imperative that the wealth of sociological and historical information be processed to comprehend the system's distinctive nature, what, Easton's critics ask, do the rather feeble categories of demands, supports, conversion process, and policy outputs contribute to our understanding? Are we not merely translating familiar and known phenomena into generic terms and empty jargon? To what extent do these terms truly aid us in better understanding political life or in directing our research efforts?
In the charged partisan atmosphere of the 1960s, it was perhaps inevitable that Easton's ostensibly value-neutral analysis would be scrutinized for tell-tale ideological loyalties. Many anti-behavioralists expended great energy and creativity in revealing the liberal assumptions they discerned at the heart of Easton's work. Systems analysis, they charged, was a politically loaded conceptualization that masqueraded as dispassionate science. Above all, they pointed out that conceiving of the political system as an equilibrium-seeking, self-balancing entity betrayed clear ideological inclinations. Like the liberal consensualist position, Easton's system's "normal" state was one of adaptive dynamic stability; it remained in balance until disturbed. What required explanation was why systems failed to adapt, why their balance-restoring mechanisms were defeated by the forces of imbalance and disintegration. System stress, overload, starvation, output paralysis, feedback loop blockage, and the like, were the pathologies of politics, a system gone wrong.
That this view differs from radical Marxist conceptions of politics goes without saying. For Marxists, stress, contradiction, conflict, and imbalance characterize the "normal" condition of the modern state. They require no special explanation. Eastonian equilibrium, Marxists contend, is necessarily contrived and, in the end, illusory. What does need to be accounted for from the Marxist perspective is the ability of the political system to survive in the face of the incessant batterings it suffers. It should, by all objective measures, succumb to revolutionary violence. Politics, for the Marxist, is only the ultimately futile attempt of the ruling interests to artificially and temporarily right the balance, which is, in

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fact, radically askers: Consequently, Easton’s claim that his equilibrium-seeking system is ideologically neutral cannot be accepted at face value. A comparison of Marxist ideas with the presumptions built into Easton's work, his critics charge, dramatizes how profoundly his own liberal axioms are woven into the fabric of his thought.
This genre of criticism goes further still. It challenges Easton's account of demands and their relation to the conversion process. Easton understands demands as being initiated by an undefined social reservoir and, subsequently, undergoing a selection process mediated by a network of "gatekeepers." The system's policy outputs are generated by the demands that actually reach the conversion process. Easton's systemic analysis has no room for those demands that fail to pass the gatekeepers. Outputs, similarly, are judged only in relation to the demands that actually make their way into the governmental process. A system that succeeds in adequately processing its demand inputs--converting them into policy outputs and passing successfully through the judgment of the feedback loop-is, presumably, in fine form.
But is it? What kinds of demands actually succeed in reaching the critical moment when inputs are converted into outputs? Are certain types of demands systematically thwarted in their drive to get a fair hearing? Are there particular categories of demands that, despairing of success, win not even attempt to become system outputs? Easton's critics charge that his consensualist liberal analysis overlooks the following: (1) demands do not derive from an undifferentiated social base; (2) they do not receive equal treatment at the hands of the gatekeepers; and (3) the feedback assessment of outputs is not uniformly sensitive to the judgments of all groups. Certain kinds of demands-let us call them "establishment" demands--win have an inside track on success while others, representing ineffective or repressed groups, can hope for little attention.
Politically ineffective groups, however, are not necessarily politically unimportant groups. The demands of a vast voiceless underclass, of national or racial minorities, of impoverished rural farmers, of a revolutionary underground, of "dissident" elements in authoritarian regimes, and of many other potentially destabilizing groups win often fail to make much headway in having their demands heard. Such groups are either incapable of translating their interests into articulate demands or, when such demands are successfully articulated, to carry them to a favorable conclusion. Nor are their grievances effectively felt in the feedback process. Typically, groups such as these are unable to generate sufficient political velocity to breech the political fortress--either because they are unable to mount an effective offensive or because their offensive is forcibly repelled.
The frustration of groups whose demands are consistently defeated cannot be calibrated with tire machinery of Easton's system. Similarly, the erosion of their support win not register because the support of the po-

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litically "relevant" groups is all the system is geared to monitor. Although their frustrations may be potentially critical for the system's stability and survival--even in the short run--they nevertheless go unrecorded. But demands that are rejected or ignored over time do not, of course, go away. They may both intensify and seek other avenues of expression. Groups having poor access to the political forum may take their needs elsewhere, outside the system, perhaps in a revolutionary manner. A revolutionary situation may, in fact, be in the offing without showing up in thc demands tire system processes. Although such systems may be deeply divided and tenuous, they will give an illusory impression of stability.
Critics draw two conclusions from these arguments. First, Easton's liberal predispositions have insinuated themselves into the seemingly transparent analytical scheme he proposes. These predispositions are evidenced in the affinity of systems analysis to equilibrium-seeking images of politics as well as in its proclivity to focus on politically dominant supports and demands. Second, the categories of systems analysis are not very useful in the conduct of political research. In the actual analysis of political realities, one is bound to dispense with Easton's categories and rely on those sources of information that knowledgeable observers have used immemorially. For example, to correct the bias of systems analysis toward politically dominant forces would require going outside Easton's notion of inputs as those demands and supports that actually impinge or the conversion process. It would involve including all those forces that general sociological, economic, cultural, and historical knowledge of the system would make apparent. But, the critics ask, if we are to base our understanding of political life on these familiar and accessible sources what does systems analysis have to offer?

SUGGESTIONS FOR FURTHER READING

Easton, D. A Systems Analysis of Political Life (New York, Wiley, 1965). Easton, D. A Framework for Political Analysis (Englewood Cliffs, N.J., Prentice Hall, 1965).
Kaplan, M. System and Process in International Politics (New York, Wile 1957).
Sutherland, J.W. A General Systems Philosophy for the Social and Behavior Sciences (New York, George Braziner, 1973).
 

David Easton
Categories for the
Systems Analysis of Politics*

The question that gives coherence and purpose to a rigorous analysis of political life as a system of behavior is: How do political systems manage to persist in a world of both stability and change? Ultimately, the search for an answer win reveal what we may call the life processes of political systems--those fundamental functions without which no system could endure--together with the typical modes of response through which systems manage to sustain them. The analysis of these processes, and of the nature and conditions of the responses, I posit as a central problem of political theory.

Political Life as an Open and Adaptive. System

Although I shall end by arguing that it is useful to interpret political life as a complex set of processes through which certain kinds of inputs are converted into the type of outputs we may call authoritative policies, decisions, and implementing actions, it is useful at the outset to take a somewhat simpler approach. We may begin by viewing political life as a system of behavior imbedded in an environment to the influences of which the political system itself is exposed and in turn reacts. Several vital considerations are implicit in this interpretation, and it is essential that we become aware of them.
First, such a point of departure for theoretical analysis assumes, without further inquiry, that political interactions in a society constitute a system of behavior. This proposition is deceptive in its simplicity. The truth is that if the idea system is used with the rigor it permits and with all its currently

*This essay is a slightly revised version of Chapter Two of my book, A Systems Analysis of Political Life (New York: John Wiley & Sons, Inc., 1965). It is reprinted here with permission of the publishers. In effect this essay summarizes my book, A Framework for Political Analysis (Englewood Cliffs, N.J.: Prentice-Hall, Inc., 1965) and points forward to the more detailed elaboration of my views now to be found in A Systems Analysis of Political Life. The value of its presence here is not only that it offers an overview of the analytic structure developed in both of these values, but also that it represents strategy toward a general theory substantially different from the strategies presented in the other essays in this book.

From David Easton, ed., Varieties of Political Theory (Englewood Cliffs, N.J., Prentice-Hall, 1966), pp. 143-154. Reprinted by permission of the author and University of Chicago Press.

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inherent implications, it provides a starting point that is already heavily weighted with consequences for a whole pattern of analysis.
Second, to the degree that we are successful in analytically isolating political life as a system, it is clear that that system cannot usefully be interpreted as existing in a void. It must be seen as surrounded by physical, sociological, social, and psychological environments. Here again, the empirical transparency of the statement ought not to distract us from its crucial theoretical significance. If we were to neglect what seems so obvious once it is asserted, it would be impossible to lay the groundwork for an analysis of how political systems manage to persist in a world of stability or change.
This brings us to a third point. What makes the identification of the environments useful and necessary is the further presupposition that political life forms an open system. By its very nature as a social system that has been analytically separated from other social systems, such a system must be interpreted as lying exposed to influences deriving from the other systems in which it is embedded. From them flows a constant stream of events and influences that shape the conditions under which the members of the system must act.
Finally, the fact that some systems do survive, whatever the buffets received from their environments, awakens us to the fact that they must have the capacity to respond to disturbances and thereby to adapt to the conditions under which they find themselves. Once we are wining to assume that political systems may be adaptive, and need not just react passively to their environmental influences, we shall be able to cut a new path through the complexities of theoretical analysis.
In a political system's internal organization, a critical property that it shares with all other social systems is an extraordinarily variable capacity to respond to the conditions under which it functions. Indeed, political systems accumulate large repertoires of mechanisms by which they may try to cope with their environments. Through these mechanisms, they may regulate their own behavior, transform their internal structure, and even go so far as to remodel their fundamental goals. Few types of systems, other than social systems, have this potentiality. In practice, students of political life cannot help but take this into account; no analysis could even begin to appeal to common sense if it did not do so. Nevertheless, this potentiality is seldom built into a theoretical structure as a central component; certainly its implications for the internal behavior of political systems have never been set forth and explored,l

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Equilibrium Analysis and Its Shortcomings

It is a major shortcoming of the one form of inquiry latent  but prevalent in political research--equilibrium analysis--that it neglects such variable capacities of systems to cope with environmental influences. Although the equilibrium approach is seldom explicitly elaborated, it has permeated a good part of political research, especially group politics2 and international relations. Of necessity, an analysis that conceives of a political system as seeking to maintain a state of equilibrium must assume the presence of environmental influences. It is these that displace the power relationships in a political system from their presumed stable state. It is then customary to analyze the  system, if only implicitly, in terms of a tendency to return to a presumed preexisting point of stability. If the system should fail to do so, it would be interpreted as moving on to a new  state of equilibrium; and then this would need to be identified and/described. A careful scrutiny of the language used reveals that equilibrium and stability are usually assumed to mean the same thing.
       Numerous conceptual empirical difficulties stand in the  way of an effective use of the equilibrium idea for the analysis of political life. Among these difficulties, there are two that are particularly relevant for present purposes.
In the first place, the equilibrium approach leaves the impression that the members of a system have only one basic goal as they seek to cope with change or disturbances: namely, to re-establish the old point of equilibrium or to move on to some new one. This is usually phrased, at least implicitly, as the search for stability, as though stability were sought above all else. In the second place, little if any attention is explicitly given to formulating the problems relating to the path that the system takes in seeking to return to its presumed old point of equilibrium or to attain a new one. It is as though the pathways taken to manage the displacements were an incidental, rather than a central, theoretical consideration.
But it is impossible to understand the processes underlying the capacity of some kind of political life to sustain itself in a society if either the objectives or the form of the responses are taken for granted. A system may well have other goals than that of reaching one or another point of equilibrium. Even though the idea of a state of equilibrium were to be used only as a theoretical norm that is never achieved, such a conception would offer a less useful theoretical approximation of reality than one that takes into account other possibilities. We would

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find it more helpful to devise a conceptual approach that recognized that members in a system may at times wish to take positive actions to destroy a previous equilibrium or even to achieve some new point of continuing disequilibrium. This is typically the case when the authorities seek to keep themselves in power by fostering internal turmoil or external dangers.
Furthermore, with respect to these variable goals, it is a primary characteristic of all systems that they are able to adopt a wide range of actions of a positive, constructive, and innovative sort for warding off or absorbing any forces of displacement. A system need not react to a disturbance just by oscillating in the neighborhood of a prior point of equilibrium or by shifting to a new one. It may cope with the disturbance by seeking to change its environment so that the exchanges between its environment and itself are no longer stressful; it may seek to insulate itself against any further influences from the environment; or the members of the system may even fundamentally transform their own relationships and modify their own goals and practices so as to improve their changes of handling the inputs from the environment. In these and other ways, a system has the capacity for creative and constructive regulation of disturbances.
It is clear that the adoption of equilibrium analysis, however latent it may be, obscures the presence of system goals that cannot be described as a state of equilibrium. It also virtually conceals the existence of varying pathways for attaining these alternative ends. For any social system, including a political one, adaptation represents more than simple adjustment to the events in its life. It is made up of efforts--limited only by the variety of human skins, resources, and ingenuity--to control, modify, or fundamentally change either the environment or the system itself, or both together. In the outcome, the system may succeed in fending off or incorporating successfully any influences stressful for it.

Minimal Concepts for a Systems Analysis

A systems analysis promises a more expansive, inclusive, and flexible theoretical structure than is available even in a thoroughly self-conscious and well-developed equilibrium approach. To do so successfully, however, a systems analysis must establish its own theoretical imperatives. At the outset, we may define a system as any set of variables regardless of the degree, of interrelationship among them. The reason for preferring this definition is that it frees us from the need to argue

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about whether or not a political system is really a system. The only question of importance about a set selected as a system to be analyzed is whether this set constitutes an interesting system. Does it help us to understand and explain some aspect of human behavior of concern to us?
As I have argued in The Political System, a political system , can be designated as the interactions through which values are authoritatively allocated for a society; this is what distinguishes a political system from other systems is its environment. This environment itself may be divided into two parts: the intrasocietal and the extrasocietal. The first consists of those systems in the same society as the political system which are not political systems due to our definition of the nature of political interactions. Intrasocietal systems include such sets of behavior, attitudes, and ideas as the economy, culture, social structure, and personalities; they are functional segments of the society of which the political system is itself a component. In a given society, the systems other than the political System are the source of many influences that create and shape the conditions under which the political system itself must operate. In a world of newly emerging political systems, we do not need to pause to illustrate the impact that a changing economy, culture, or social structure may have upon political life.
The second part of the environment, the extrasocietal includes all those systems that lie outside the given society itself. They are functional components of all international society, a suprasystem of which any single society is part. The international cultural system is an example of an extrasocietal system.
Taken together, these two classes of systems--the intra- and extra-societal--which we conceive to lie outside a political system, comprise the total environment of a political system.6 From these sources arise influences that are of consequence for possible stress on the political system. Disturbances is a concept that we may use to refer to those influences from the total environment of a system that act upon the system, and thereby change it. Not all disturbances need strain the system: Some may be favorable to the persistence of the system; others may be entirely neutral with regard to stress. But many can be expected to contribute to stress.
When may we say that stress occurs? This question involves us in a rather complex idea, one that embodies several subsidiary notions. All political systems as such are distinguished by the fact that if we arc to be able to describe them as persisting, we must attribute to them the successful fulfillment

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of two functions. They must be able to allocate values for a society, and they must manage to induce most members to accept these allocations as binding, at least for most of the time. These two properties distinguish political systems from other kinds of social systems.
Hence, these two distinctive properties--the allocations of values for a society/and the relative frequency of compliance with them--are the essential variables of political life. But for their presence, we would not be able to say that a society has any political life. And we may here take it for granted that no society could exist without some kind of political system; elsewhere I have sought to demonstrate this in detail.7
One of the important reasons for identifying these essential variables is that they give us a way of establishing when and how the disturbances acting upon a system threaten to cause it stress. We can say that stress occurs when there is a danger that the essential variables will be pushed beyond what we may designate as their critical range. What this means is that something may be happening in the environment-the system suffers total defeat at the hands of an enemy, or a severe economic crisis arouses widespread disorganization in and disaffection from the system. Let us assume that, as a result, either the authorities are consistently unable to make decisions, or the decisions they do make are no longer regularly accepted as binding. Under these conditions, authoritative allocations of values are no longer possible, and the society collapses for want of a system of behavior to fulfill one of its vital functions.
 Here we cannot help but accept the interpretation that the political system had come under stress, so severe that any and every possibility for the persistence of a system for that society had disappeared. But frequently the disruption of a political system is not that complete; even though stress is present, the system continues to persist in some form. Severe as a crisis may be, it still may be possible for the authorities to be able to make some kinds of decisions and to get them accepted with at least minimal frequency, so that some of the problems typically subjected to political settlements can be handled.
In other words, it is not always a matter of whether or not the essential variables are operating. It is possible that they may only be somewhat displaced, as when the authorities are partially unable to make decisions or to get them accepted with complete regularity. Under these circumstances, the essential variables remain within some normal range of operation; they may be under stress, but not to a sufficient degree to displace them beyond a determinable critical point. As long as the sys-

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term keeps its essential variables operating within their critical range, some kind of system call be said to persist.
As we have seen, every system has the capacity to cope with stress on its essential variables. Not that systems always do so; a system may collapse precisely because it has failed to take measures appropriate for handling the impending stress. But it is the existence of the capacity to respond to stress that is of paramount importance. The kind of response (if any) actually undertaken win help us to evaluate the probability that the system win be able to ward off the stress. Raising the question of the nature of the response to stress points up the special objectives and merit of a systems analysis of political life. It is especially suited for interpreting the behavior of the members in a system in the light of the consequences this behavior has for alleviating or aggravating stress upon the essential variables.

The Linkage Variables Between Systems

But a fundamental problem remains: How do the potentially stressful conditions from the environment communicate themselves to a political system? After all, common sense tells us that there is an enormous variety of environmental influences at work on a system. Do we have to treat each change in the environment as a separate and unique disturbance, the specific effects of which have to be independently worked out?
If this were indeed the case, the problems of systematic analysis would be virtually insurmountable. But if we can devise a way for generalizing our method for handling the impact of the environment on the system, there would be some hope of reducing the enormous variety of influences into a manageable number of indicators. This is precisely what I seek to do through the use of the concepts of  inputs and outputs.
How are we to describe these inputs and outputs? Because of the analytic distinction that I have been making between a political system and its parametric or environmental systems, it is useful to interpret the influences associated with the behavior of persons in the environment as exchanges or transactions that, can cross the boundaries of the political system. Exchanges will be used whenever we wish to refer to the mutuality of the relationships between the political system and the other--systems in the environment. Transactions will be used when we wish to emphasize the movement of an effect in one direction, from an environmental system to the political system,

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or the reverse, without being concerned at the time about the reactive behavior of the other system.
Up to this point, there is little to dispute. If systems were not in some way coupled together, all analytically identifiable aspects of behavior in society would be independent of each other, a patently unlikely condition. What makes the fact of this coupling more than a mere truism, however, is the proposal of a way to trace out the complex exchanges so that we can readily reduce their immense variety to theoretically and empirically manageable proportions.
To accomplish this, I have proposed that we condense the major and significant environmental influences into a few indicators. Through the examination of these we should be able, to appraise and follow through the potential impact of environmental events on the system. With this objective in mind, I have designated the effects that are transmitted across the boundary of a system toward some other system as the outputs of the first system and hence, symmetrically, as the inputs of the second system. A transaction or an exchange between systems win therefore be viewed as a linkage between them in the form of an input-output relationship.

Demands and Supports as Input Indicators

The value of inputs as a concept is that through their use we shall find it possible to capture the effect of the vast variety of events and conditions in the environment as they pertain to the persistence of a political system. Without using the concept of input, it would be difficult to delineate the precise operational ..,way in-which the behavior in the various sectors of society affects what happens in the political sphere. Inputs will serve as summary variables that concentrate and mirror everything  in the environment that is relevant to political stress. Thereby the concept of inputs serves as a powerful analytic tool.
 The extent to which inputs can be used as summary variables will depend, however, upon how we define them. We might conceive of them in their broadest sense. In that case, we would interpret them as including any event external to the system that alters, modifies, or affects the system in any way? But if we used the concept in so broad a fashion, we would never be able to exhaust the list of inputs acting upon a system. Virtually every parametric event and condition would have some significance for the operations of a political system at the focus of attention; a concept so inclusive that it does not

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help us to organize and simplify reality would defeat its own purposes. But as I have already intimated, we can greatly simplify the task of analyzing the impact of the environment if we restrict our attention to certain kinds of inputs that can be used as indicators to sum up the most important effects, in terms of their contributions to stress, that cross the boundary from the parametric to the political systems. In this way, we would free ourselves from the need to deal with and trace out separately the consequences of each type of environmental event.
As the theoretical tool for this purpose, it is helpful to view the major environmental influences as focusing in two major inputs: demands and support." Through them, a wide range of activities in the environment can be channeled, mirrored, summarized, and brought to before upon political life. Hence, they are key indicators of thc way in which environmental influences and conditions modify and shape the operations of the political system. If we wish, we may say that it is through fluctuations in the inputs of demands and support that we shall find the effects of the environmental systems transmitted to the political system.

Outputs and Feedback

In a comparable way, the idea of outputs helps us to organize 33 the consequences flowing from the behavior of the members of the system rather than from actions in the environment. Our primary concern is, to be sure, with the functioning of the political system. For understanding political phenomena, we would have no need to be concerned with the consequences in and of themselves that political actions have for the environmental systems. This is a problem that can be better handled by theories dealing with the operations of the economy, culture, or any of the other parametric systems.
But the activities of the members of the system may well 34 have some importance for their own subsequent actions or conditions. To the extent that this is so, we cannot entirely neglect those actions that do flow out of a system into its environment. As in the case of inputs, however, there is an immense amount of activity that takes place within a political system. How are we to isolate the portion relevant to an understanding of the way in which systems manage to persist?
A useful way of simplifying and organizing our perceptions 35 of the behavior of the members of the system (as reflected in

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their demands and support) is to do so in terms of the effects these inputs have on what we may call the political outputs. These are the decisions and actions of the authorities. Not that the complex political processes internal to a system that have been the subject of inquiry for so many decades in political science will be considered in any way irrelevant. Who controls whom in the various decision-making processes will continue to be a vital concern, since the pattern of power relationships helps to determine the nature of the outputs. But the formulation of a conceptual structure for this aspect of a political system would draw us onto a different level of analysis. Here, I am only seeking economical ways of summarizing--not of investigating--the outcomes of these internal political processes, which can, I suggest, be usefully conceptualized as the outputs of the authorities. Through them, we are able to trace out the consequences of behavior within a political system for its environment.
Outputs not only help to influence events in the broader society of which the system is a part, but also, in doing so, they help to determine each succeeding round of inputs that finds its way into the political system. There is a feedback loop, the identification of which helps us to explain the processes through which the system may cope with stress. Through it, the system may take advantage of what has been happening by trying to adjust its future behavior.
When we speak of the systems as acting, however, we must be careful not to reify the system itself. We must bear in mind that all systems, to make collective action possible, have those who usually speak in the name or on behalf of the system. We may designate these as the authorities. If actions are to be taken to satisfy demands or create conditions that will do so, information must be fed back, at least to these authorities, about the effects of each round of outputs. Without information-feedback about what is happening in the system, the authorities would have to operate in the dark.
If we take as our analytic point of departure the capacity of a system to persist, and if we view as one of the possible and important sources of stress a possible drop in support below some specifiable minimum, we can appreciate the importance of information-feedback to the authorities. The authorities need not necessarily seek to bolster the input of support for themselves or for the system as a whole. But if they should wish to do so--and their own survival may well force them to do so--information about the effects of each round of outputs and about the changing conditions under which the

 
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members finds themselves is essential. It enables them to take whatever action they feel is necessary to keep support at some minimal level.
For this reason, a model of this kind suggests that exploration of the operations of the feedback processes is of vital significance. Anything that serves to delay, distort, or sever the flow of information to the authorities interferes with their capacity to take action, if so desired, to keep support at a level high enough to ensure the persistence of the system.
The feedback loop itself has a number of parts worthy of detailed investigation. It consists of the production of outputs by the authorities, a response by the members of the society to these outputs, the communication of information about this response to the authorities, and finally, possible succeeding actions by the authorities. Thereby a new round of outputs, response, information-feedback, and reaction by the authorities is set in motion, forming a seamless web of activities. What happens in this feedback thus has a profound influence on the capacity of a system to cope with stress and persist.

A Flow Model of the Political System

It is clear from what has been said that this mode of analysis enables and indeed compels us to analyze a political system in dynamic terms. Not only do we see that a political system gets something done through its outputs, but we are also sensitized to the fact that what the system does may influence each successive stage of behavior. We appreciate the urgent need to interpret political processes as a continuous and interlinked flow of behavior.
If we were to be content with what is basically a static picture of a political system, we might be inclined to stop at this point. Indeed, most political research today does just this. It is concerned with exploring all those intricate subsidiary processes through which decisions are made and put into effect. Therefore, insofar as we were concerned with how influence is used in formulating and putting into effect various kinds of policies or decisions, the model to this point would be an adequate if minimal first approximation.
But the critical problem confronting political theory is not just to develop a conceptual apparatus for understanding the factors that contribute to the kinds of decisions a system makes--that is, to formulate a theory of political allocations. As I have indicated, theory needs to find out how any kind

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of system manages to persist long enough to continue to make such decisions, and how it deals with the stress to which it may be subjected at any time. For this reason we cannot accept outputs as the terminus of either the political processes or our interest in them. Thus it is important to note, as part of this model, that the outputs of the conversion process characteristically feed back upon the system and thereby shape its subsequent behavior. It is this feature, together with the capacity of a system to take constructive actions, that enables a system to try to adapt or to cope with possible stress.
 Thus, a systems analysis of political life rests on the idea of a system imbedded in an environment and subject to possible environmental influences that threaten to drive the essential , variables of the system beyond their critical range. Such an analysis suggests that, to persist, the system must be capable of responding with measures that alleviate that stress. The actions of the authorities are particularly critical in this respect. But if they are to be able to respond, they must be in a position to obtain information about what is happening so that they may react insofar as they desire, or are compelled, to do so. With information, they may be able to maintain a minimal level of support for the system.
A systems analysis poses certain major questions, answers to which would help to flesh out the skeletal outline presented here: What precisely is the nature of the influences acting upon a political system? How are they communicated to a system? In what ways, if any, have systems typically sought to cope with such stress? What kinds of feedback processes must exist in any system if it is to acquire and exploit the potential for acting so as to ameliorate these conditions of stress? How do different types of systems--modern or developing, democratic or authoritarian--differ with regard to their types of inputs, outputs, and internal conversion and feedback processes? What effects do these differences have upon the capacity of the system to persist in the face of stress?
The task of theory construction is not of course to give substantive answers to these questions initially. Rather, it is both to formulate the appropriate questions and to devise appropriate ways for seeking answers.'

Notes
1. K. W. Deutsch, in The Nerves of Government (New York: Free Press of Glencoe, Inc., 1963), has considered the consequences of the response capacity of political systems in international affairs, although in very general terms. Some work has also been done for formal organizations. See J. W. Forrester, Industrial Dynamics (NewYork: MIT Press and John Wiley & Sons, Inc., 1961); and W. R. Din, "The Impact of Environment on Organizational Development," in S. Mailick and E. H. Van ,4ess, Concepts and Issues in Administrative Behavior (Englewood Cliffs, N.J.: Prentice-Hall, Inc., 1962), pp. 94-109.
2. See David Easton, The Political System (New York: Alfred A. Knopf, Inc., 1953), Chapter Eleven.
3. In "Limits of the Equilibrium Model in Social Research," Behavioral Science, I (1956): 96-104, I discuss difficulties created by the fact that social scientists typically fail to distinguish between stability and equilibrium. WL often assume that a state of equilibrium must always refer to a stable condition, but in fact there are at least two other kinds of equilibria: neutral and unstable.
4. Easton, "Limits of the Equilibrium Model."
5. J. A. Schumpeter, Business Cycles (New York: McGraw-Hill Book Company, 1939), especially in Chapter Two, discusses the idea of equilibrium as a theoretical norm.
6. The total environment is presented in Table 1, Chapter Five, of A Framework for Political Analysis. That volume also includes a full discussion of the various components of the environment.
7. In David Easton, A Theoretical Approach to Authority, Office of Naval Research, Technical Report No. 17 (Stanford, California: Department of Economics, 1955).
8. I am confining my remarks here to external sources of inputs. For the possibility of inputs deriving from internal sources and therefore constituting withinputs, see A Framework for Political Analysis, Chapter Seven.
9. I have addressed myself to these objectives in A Framework for Political Analysis and A Systems Analysis of Political Life.