WHY do our best-laid plans go oft astray? Cities enact rent control in order to ensure an adequate supply of affordable housing, which discourages further investment in residential property and makes affordable housing harder to find. We ban certain drugs in order to protect society from their adverse consequences, thereby encouraging an illegal narcotics traffic that enriches criminals, fuels urban violence, and complicates relations with foreign governments. We welcome the globalization of world markets and hail the Asian economic miracle, only to be surprised when a currency crisis in Thailand triggers a financial panic in Korea and Japan.
Why is the human experience filled with unpleasant surprises like these? The main reason, as Robert Jervis makes clear in his intriguing new book, System Effects, is the difficulty of predicting how complex systems will behave. Drawing on a diverse body of scholarly research and a wealth of illuminating examples, Jervis shows that "system effects" are an important and often overlooked part of social and political life. And though he focuses most of his attention on issues of international politics, where system effects are especially prevalent, his insights will capture the imagination of those who puzzle over other social problems as well.
For Jervis, a system effect exists whenever "(a) a set of units or elements is interconnected so that changes in some elements or their relations produce changes in other parts of the system, and (b) the entire system exhibits properties and behaviors that are different from those of the parts." Thus a system can be a physical entity, such as the solar system; a living organism; or a social organization, such as a free market, a neighborhood, or an international alliance. Although the boundaries between different systems are largely arbitrary (for example, individual human beings are systems in their own right and also part of a nearly infinite number of social systems), system effects will be present whenever separate parts are linked in a larger whole.
According to Jervis, system effects occur for three distinct but interrelated reasons. First, in addition to the direct effects of any action, the interconnections within a system produce indirect and delayed effects. For example, altering the federal tax code has a direct effect on government revenues, and it also has indirect effects on investment decisions, consumer spending, and the incomes of accountants and lawyers.
Second, when there are more than two actors in a system, the relationship between any two will be determined not just by how they act toward each other but also by the interactions among the other members of the system. In a marriage, for example, the degree of harmony between husband and wife is determined not only by their own compatibility but also by the presence or absence of attractive co-workers, difficult children, and malevolent in-laws. Similarly, relations between two states are often affected primarily by what other states do -- as when two states form an alliance solely because a third state threatens them both.
Third, relations in a system are interactive rather than additive. Actions may not lead directly to an intended result, because the outcome also depends on how the other elements in the system respond. For example, one might think that acquiring a player like Shaquille O'Neal would make any basketball team stronger, but this strategy would backfire if his skills did not mesh well with those of the other players on the team. In a system the results of any particular move may depend on the moves that other actors make, and actions taken at one point in time may alter the entire system in ways that lead to very different behavior at a later stage. Relations of cause and effect are often murky, and determining who is responsible for what can be nearly impossible.
Because system effects are everywhere, Jervis emphasizes, "we can never do merely one thing." Any step we take will have an infinite number of consequences, some that we intend and others that we neither intend nor foresee. A military buildup may deter a threatening adversary and help to preserve peace, for example, but it may also divert funds from other social needs, encourage one's allies to free-ride, and cause formerly neutral states to become friendlier with one's rivals. The more complex the system and the denser the interactions between the parts, the more difficult it is to anticipate the full effects of any action.
The stability of a given system is often determined by whether the interactions among the parts are characterized by negative or positive feedback. Negative feedback occurs when the elements of a system act to dampen any disturbance (as a thermostat responds to a shift in temperature), thereby tending to preserve the system in its initial state. In contrast, positive feedback reinforces the disturbance and magnifies its effects. "Were it not for negative feedback," Jervis points out, "there would be no stability as patterns would not last long enough to permit organized society. Without positive feedback, there could be no change and growth."
In international politics the classic example of negative feedback is the balance of power. The fear of being dominated usually leads weaker states to join forces against stronger or more threatening ones, which is why trying to amass more and more power can be counterproductive and why it has been so difficult for any single state to establish an enduring hegemony over the others. The same logic inspired the system of checks and balances that is embedded in the U.S. Constitution. To enhance the stability of the new republic and to prevent it from falling prey to tyranny, the Founding Fathers divided power among the various branches of government and made it easy for factions to combine, thereby making it hard for a majority consistently to dominate the rest.
When positive feedback is prevalent, systems do not behave in this self-correcting fashion, and small causes may have very large effects. Just as a single snowball can start an avalanche when conditions are right, an entire neighborhood can be transformed if a minority population reaches a "tipping point" that persuades the predominant group to leave en masse. Positive feedback is central to the familiar domino theory, which argues that a single setback can damage a state's credibility, embolden its rivals, and demoralize its allies, thus making subsequent defeats likely. When positive feedback is at work, in short, instability is the norm, and rapid and unforeseen changes are to be expected.
Unfortunately for would-be social engineers, both kinds of feedback can occur in most systems. This makes it difficult to know which behavior to expect and difficult to predict the effects of a policy change. States in the international system usually balance against powerful aggressors, but occasionally dominoes do fall and states do jump on the bandwagon. Sometimes issuing a threat can trigger an escalating spiral of mutually reinforcing hostility, but at other times a threat can deter a potential aggressor or lead both sides to make a conscious effort to relax tensions. Although Jervis does identify some of the conditions that make positive or negative feedback likely, statecraft remains a difficult art, because it is hard to know in advance which behavior will occur.
DESPITE these uncertainties, Jervis's analysis yields a number of useful generalizations about the behavior of groups -- especially states -- that are engaged in competitive activities. In a chapter devoted to international bargaining, Jervis shows how leverage over others often depends less on a state's power or resolve than on the structure of the system and the various relations among its other members. In general, states gain leverage when they have a choice of partners, especially when those others have nowhere else to turn. Among the implications of this is that great powers can maximize their leverage by occupying a pivotal position between two hostile powers, as Bismarck's Germany did vis-à-vis Austria and Russia, and as the United States tried to do vis-à-vis the Soviet Union and China. Another chapter explains why a pivotal position is hard to achieve and even harder to maintain. Jervis argues that social systems tend to become more "consistent" over time, because the members of different groups will form ties with one another and adopt a negative attitude toward one another's enemies. This tendency is partly a reflection of underlying interests (states with similar goals and preferences naturally tend to band together), but it also occurs because a state that tries to stay on good terms with two rivals will face constant pressure from both to prove its loyalty. If pressed hard enough, a pivotal state will eventually have to choose a side, lest the two rivals conclude that the state is insincere and not to be trusted.
Pressure for consistency is greatest when competition within a system is intense. The leading actors pressure the other members to join them and discourage their allies from cooperating with the enemy camp. Thus inner-city youths are often pressured to join street gangs whether they want to or not, and the United States and the Soviet Union were intolerant of even minor states' neutrality throughout the Cold War. In more relaxed settings, in contrast, actors have room to maintain relationships that are partly at odds with their other connections. Thus intermarriage flourished in the former Yugoslavia as long as Tito was around to guarantee ethnic peace. The subsequent outbreak of war forced even Bosnians of mixed ancestry to adopt a single ethnic identity so as to gain the support and protection of the other members of the ethnic group.
System effects explain many other aspects of political life as well. For instance, the omnipresence of system effects explains why the optimism that accompanies the end of a major war is often misplaced. Because "we can never do merely one thing," today's victories will contain the seeds of tomorrow's troubles. The Western allies won a "war to end war" in 1918, but their victory helped to bring Hitler to power and created a series of weak and vulnerable states in Central Europe, thereby setting the stage for the Second World War. The Allied triumph in 1945 was supposed to redeem the promise of 1918 by making the world "safe for democracy"; instead it launched a long and bitter struggle between the United States and the Soviet Union. The eventual collapse of the Soviet Union was good news for the United States and its allies, but its effects included the 1991 Persian Gulf War, an increasingly delicate relationship between the United States and China, and an unforeseen resurgence of xenophobic nationalism and ethnic conflict.
A systemic perspective also places political leaders in a new light. As Jervis points out, it is harder to judge someone's behavior fairly when system effects are present, because these constraints may force one to do things one would prefer to avoid, and because the results of one's actions may not be what one intended. Bill Clinton may not be as unprincipled and opportunistic as he sometimes appears; he is operating in a political system that rewards flexibility, penalizes those who cling to unpopular positions, and places relatively little value on personal integrity. Similarly, the thuggish behavior of Saddam Hussein looks different when we take Iraq's position in the system into account. Americans have been encouraged to see the Iraqi leader as the embodiment of evil aggression, but his state is relatively weak, internally divided, and surrounded by powerful enemies. Thus his desire for advanced weaponry and his attempt to grab Kuwait's oil wealth may have been inspired more by Iraq's position in the system than by his own megalomania, and the tendency to view Iraq's behavior solely in terms of Saddam Hussein's personality may explain why our policy toward Baghdad has been so ineffective.
Finally, a systemic perspective highlights both the favorable global position of the United States and the difficulties that such a position creates. The United States is the most secure great power in modern history, and the least dependent on outside help. It has the world's largest and most advanced economy, a robust nuclear deterrent, and conventional military forces that are far stronger than those of any other state. Unlike the major powers of Europe and Asia, it has no potential rivals in its immediate neighborhood. And because the United States is separated by two oceans from the other centers of world power, its strength is less threatening to others and thus less likely to cause them to balance against it. Most states need allies in order to be secure, but the United States can be remarkably secure all by itself. This does not mean that we have no overseas interests or that our allies are of no value, but it does mean that our allies need us far more than we need them.
As Jervis's analysis of international bargaining suggests, the United States gains considerable leverage from its pivotal position in the system. Our freedom of action is the main reason why the old cry of "Yankee, go home!" has been replaced by "Americans, please stay!" And it also explains why Europeans and Asians grumble about U.S. dominance but are still reluctant to challenge it.
Yet our unparalleled advantages make it more difficult for us to decide what our grand strategy should be. Pundits now deplore the loss of the bipartisan "Cold War consensus" and bemoan the lack of strategic vision in contemporary U.S. foreign policy. But these problems are not caused by failures of leadership; they are a direct result of the unusual position that the United States now occupies. During the Cold War the presence of the Soviet threat focused the mind; today the absence of a major threat to any vital interests makes it harder to achieve consensus on anything.
Unfortunately, thinking in systemic terms cannot provide us with a definitive answer. One could argue, for example, that a reduced U.S. role would force our allies to provide for their own security and would eventually lead to an increase in security competition among the various Eurasian powers. Not only would this enable us to reduce our defense spending (which as a percentage of GNP is still roughly half again as large as the NATO average), but U.S. influence might even increase if the other major powers were more at odds with one another. So withdrawing U.S. forces from Europe and Asia could be in our long-term national interest precisely because it would tend to destabilize relations among the other members of the system and help us to maintain our pivotal role.
The possible system effects do not end there, however. Renewed rivalry in Europe or Asia would threaten the liberal economic order upon which some of our current prosperity depends, and thus create indirect economic costs for a broad segment of the U.S. population. More important, a return to great-power rivalry in Eurasia would also increase the risk of a great-power war, and the United States has in the past found it hard to remain aloof from such conflicts. If we value peace and prosperity, therefore, an equally good case can be made for maintaining our present commitments.
Thinking through the system effects cannot stop there, either. Because our external position is so favorable, our leaders face difficulty in maintaining public support for an extensive array of international obligations. And the very fact that the United States could easily withdraw means that our allies have good reason to question our commitment, even if we do intend to stay. Paradoxically, if we choose to maintain our current overseas commitments, we may have to do more than we want to in order to persuade our allies that our promises are still good. There is an obvious but unfortunate link between these two problems: If we do too much, our allies will take advantage of our support and we will be likely to get embroiled in conflicts that have no bearing on our security, thereby increasing domestic pressure to withdraw completely. If we do too little, our allies will lose faith in us and begin to make other arrangements, which could eventually increase the risk of war. So how large should the U.S. role be? Who knows?
THIS sort of indeterminacy is the main limitation of any systemic approach, even in the hands of a theorist as knowledgeable and perceptive as Robert Jervis. It is usually impossible to forecast all the system effects with confidence, and the line between success and failure may be very fine indeed. Although Jervis leaves little doubt that system effects are pervasive and important, his book cannot tell us which ones to worry about most and cannot help us to eliminate the possibility of calamitous miscalculation. What advice does Jervis offer? Policy conceived in a system, he suggests, must be conceived in holistic terms. One approach is to try to constrain what the other parts of the system can do, so that their responses do not undermine the purpose of an initiative. For example, food stamps cannot be used to buy lottery tickets or cigarettes, and alliance treaties often commit the signatories to help each other only when one or both are victims of an unprovoked attack.
Another option is to use the interconnections in a system to accomplish one's goals indirectly. Thus New York transit officials were able to reduce the "tagging" of subway cars with spray paint not by patrolling the tracks or by arresting graffiti artists but simply by cleaning each train at the end of its daily service. Once the taggers realized that their efforts would not last long enough to be seen, the prevalence of graffiti dropped dramatically. Similarly, the United States and the Soviet Union waged their competition not by attacking each other directly but by each supporting an array of allies and clients who could put pressure on the allies of the other side. This turned out to be a terrific strategy for the West, because our allies were generally much more powerful, stable, and competent than Moscow's.
A third approach is to devise a more comprehensive strategy, whereby certain actions are designed to achieve the main goal(s) and others are intended to magnify positive effects or to compensate for negative consequences. Thus efforts to reduce tariff barriers can be supplemented with job training and placement programs for unemployed workers, and "welfare to work" programs might be combined with improved mass transit and child-care options, so that working mothers could actually get to their jobs and be confident that their children were in good hands while they were away. Similar thinking underlies recent efforts in depleted urban areas to create "empowerment zones," which are based on the belief that healthy communities are sustained by synergies among businesses, schools, churches, and other institutions, and that providing one or two elements will not resurrect a neighborhood if the other elements are missing.
These prescriptions also tell us why system effects are often ignored. Overcoming the complex interactions within a system may require a multifaceted approach, but as the Clinton Administration's ill-fated health-care plan revealed, assembling the political support for a complicated program can be difficult. In addition, politicians have notoriously short time horizons, and are tempted to ignore adverse consequences that aren't likely to materialize until after the next election. It is not surprising, therefore, that politicians are often drawn to simplistic plans even when they are unlikely to work and may make things worse.
Viewed as a whole, System Effects offers a sobering and valuable moral. Because everything is connected to everything else, even our greatest accomplishments will sow the seeds of future problems. Accepting that fact is itself an achievement, however, if it frees us from a fruitless search for "magic bullets" or an unwarranted faith in the perfectibility of human societies.