A Short Comment on the Long Peace

by Erik Gartzke

The Long Peace is not an “it,” produced by a single monolithic cause or set of causes, but is instead a “they” of different, coincident factors.  Perpetuating such a peace in its current complex form will indeed prove daunting.  However, this does not mean that the world need descend again into darkness and carnage.  We can benefit from elements of the Long Peace.   The task is to identify which elements of the peace perpetuate where, and why. 

The Long Peace can be parsed into at least four distinct empirical relationships:

1.)   The hierarchical organization of the most powerful nations in the period into two competing ideological blocs anticipated, but failed to produce, major war.

2.)   Developed democracies have been much less likely to fight each other.

3.)   Developed democracies have not proven less willing/able to fight non-democracies.

4.)   Every other combination of states behaved more-or-less like they always have. 

Let’s take on the first relationship here, since arguably it is the most important.  The peace among democracies would scarcely have been noticed if major war had broken out among the East and West in that past 60 years.   At the same time, war between developing states is either nothing new or the product of what used to be called neo-imperialism and is now more fashionably described as policing the global commons.  The fact that powerful nations attack the weak, but that weak nations seldom initiate such contests is hardly remarkable.  The manner in which developed/powerful states deter or coerce conflict in the developing world is a subject worthy of attention, but is something that must be addressed elsewhere.  

The key feature of the Long Peace is really that the Cold War never got hot.  Most scholars point to structural (bipolarity) or strategic (nuclear deterrence) factors to explain Cold War stability.  The structural conditions of the Cold War are unlikely to repeat themselves in the coming decades, implying that Cold War stability should not persist.  This was pointed out by realists in the 1990s (Mearsheimer, Waltz).  Yet, the Long Peace of the Cold War period has persisted for twenty years, implying that structural/strategic factors are not necessary for stability.  Lieber and Press in The Rise of U.S. Nuclear Primacy suggest that the United States could today conduct a successful first strike against Russia, China, or both.  If Cold War opponents were held in check by MAD, or bipolarity, then nuclear primacy/hegemony should imply the opposite.  We observe that the Long Peace persists regardless of primacy.

A different explanation for Cold War stability lies in the ideological nature of the struggle. Stability results when no nation perceives a benefit from acting aggressively.  Nations could be inhibited by war risks (bipolarity), or costs (nuclear deterrence), but these theories tend to run into logical problems stemming from the zero-sum nature of conflict, and from the ability of actors to forge bargains preempting fighting; if cost inhibits me, it encourages my enemies, and so on.  It is much easier to account for a lack of aggression by arguing that neither side sees a sufficient benefit in the outcomes likely to result from war.  The United States and Canada neither deter nor balance one another.  They just lack reasons to fight, perhaps because neither covets the other’s territory and each prefers an organization and disposition of international politics that looks similar enough to what the other prefers. 

In contrast to the actions of previous world powers, the United States in particular has not been much interested in accumulating additional territory.  Instead, it desires to influence the politics of other nations, and the conditions under which nations interact and decisions are made in world affairs.  This shift in emphasis from competition over land and tangible goods to attempts to influence made it possible for the United States to adopt containment (e.g.,  Kennan’s long telegram).  For its part, the Soviet Union — after an initial conquests to create buffer states — was able to substitute the export of domestic revolution for direct confrontation with the West.  The fact that the conflict was over states of affairs rather than stuff meant that both sides were able to, in effect, wait out the collapse of the other.

The United States and the Soviet Union clearly envisioned very different world orders.  This could have led to war.  Yet, it was unclear how a general war would bring about conditions either side preferred.   It is much more difficult to change the preferences of people and societies than to simply occupy land, as both sides discovered in various fruitless and expensive “proxy wars.”  Given the intractability of each side’s goals to a military solution, both were willing to wait-and-see.  Ironically, the Soviet Union’s initial attempt to pursue security through territory meant that it faced economic burdens that hastened its downfall. 

It seems unlikely today that any nation will adopt a grand strategy similar to that of the Soviet Union, or indeed pursue territorial aggrandizement, as is so common in history.  If for example China adopts aggressive territorial objectives, it will no doubt prove counter-productive just as it did for the Soviet Union.  This seems to have been one of the insights of Deng Xiaoping, who recognized that China’s future lay in commerce rather than conquest.  It is very possible that growing Chinese prosperity will both reduce the basis for territorial conflict between China and the West, and increase mutual interests.  Even if differences remain, both sides may well conclude that there is little point in acting them out through military force.  The insignificance of territory as a basis for war in the modern world, and the different nature of policy conflict, sometimes more intense but also the opposite, is a major change in world affairs, something that is worth pursuing as its own blog segment. 



Erik Gartzke is an associate professor of political science at UC San Diego. Gartzke’s primary area of study involves the impact of information and institutions on war and peace. He applies bargaining theory, rational choice institutional theory, concepts of power and social identity, and statistical analysis to four substantive areas of interest: 1) The liberal peace, 2) international institutions, 3) diplomacy, and 4) the system overall.

By allandafoe Posted in GT2030

The Long Peace: Systematic Trends and Unknown Unknowns

by Steven Pinker

Like the other contributors to this conversation, I agree with the statement attributed to Yogi Berra that predictions are hard, especially about the future. No responsible person can predict with certainty whether the Long Peace among great powers and developed states will persist. And because we can witness the unfolding of only one universe one time, any statement of probability can be no more than a statement the theorist’s level of subjective confidence.

Still, that level of confidence can be justified to varying degrees, and it seems to me the quantitative trends underlying The Long Peace (nicely superimposed into a single graph by Allan Dafoe in his introduction) reflect genuine changes in the international system. That is, they are not just a gambler’s lucky streak that is sure to run out, an artifact of the way that wars and their human costs are counted, or a temporary lull in an inexorable cycle.  As such they support a reasonable degree of confidence that The Long Peace will persist (subject to a class of exceptions I will present at the end of this essay).

None of the reasons to dismiss the trends underlying The Long Peace strike me as sound. The wisecracks about the man plummeting off the skyscraper shouting “So far so good!” and the turkey on the eve of Thanksgiving celebrating the 364-day period of coexistence between humans and turkeys respectively assume that history is driven by an inexorable directional force or by a strict cycle. Neither theory of history is supported by data on long-term trends in wars involving great powers or developed countries. In Better Angels I summarized these data (from Jack Levy, Lewis Richardson, Peter Brecke, and others) as a superposition of four patterns (p. 192): (1) No cycles; (2) A big dose of randomness; (3) A long-term escalation in the destructiveness of war, which made a substantial U-turn after 1945; and (4) Long-term declines in the frequency and duration of war. Multiplying the trends in (3) and (4) yields the overall decline in war that we call The Long Peace, and Factor (2) should keep us humble and cautious. But nothing supports the systematic pessimism of the fables about plummeting men or complacent turkeys.

Nor do the cautionary tales about pre-World-War I optimism tell us much, except that we should always be cautious. First, the infamous Norman Angell did not predict that war was impossible, only that it was economically irrational. He feared that ideology and fear might lead the leaders of great powers to blunder into a disastrous war, and he was right. Second, though the world of a century ago had seen unprecedented levels of trade and economic integration, Bruce Russett and John Oneal have shown that when they are measured quantitatively (as a proportion of GDP) they are a tiny fraction of the levels the world has seen since 1945 (Better Angels, p. 286). Russett and Oneal’s two other statistical predictors of peace (democracy and membership in intergovernmental organizations) are also far higher today, and other indicators of war-readiness such as the prevalence and length of conscription, the proportion of the population in uniform, overall prosperity, and the political participation of women are also more favorable today. In the realm of ideas, romantic militarism and nationalism have ceded ground to war aversion and liberal humanism, and of course nowadays we have knowledge of two destructive world wars and an awareness of the possibility of a nuclear catastrophe. In no other realm of human experience could one credibly say that we have learned nothing in the past century and that the assessments of today are no more trustworthy than those of a hundred years ago.

There is, of course, a tragic-poetic vision of the human condition in which we are condemned to repeat history, to be felled by our own hubris, to regress to our nature red in tooth and claw, and so on, but it is not grounded in historical or biological fact. If The Long Peace endures, it would not be the first time in history that a longstanding barbaric institution has been abolished or at least decimated. Wars involving great powers and developed states could very well join human sacrifice, chattel slavery, public torture-executions, auto-da-fés, debtors’ prisons, bear-baiting, foot-binding, gentlemanly dueling, witch hunts, and trephination on the ash heap of history.

Nor does a realistic, nonromantic view of human nature require perpetual war (and I can speak with some authority on this, having championed a thoroughly unsentimental understanding of the crooked timber of humanity in How the Mind Works and The Blank Slate).  Though Homo sapiens undoubtedly evolved with violent instincts, those instincts are triggered by particular circumstances; they are not a hydraulic urge that must periodically be discharged. And though we evolved motives that can erupt in violence, we also evolved motives that can inhibit violence, including self-control, empathy, a sense of fairness, and open-ended cognitive mechanisms that can devise technologies for reducing violence.

None of this is to say that The Long Peace must endure. On top of the many systematic trends that militate against the resumption of great-power and developed-state war, there are the black swans, long tails, and unknown unknowns that could poke big spikes up into the declining gradient. Perhaps there is some charismatic politician working his way up through the Chinese nomenklatura who dreams of rectifying the intolerable insult of Taiwan once and for all, provoking an American or international response. Perhaps an aging Putin will seek historical immortality and restore Russian greatness by swallowing a former Soviet republic or two. Perhaps terrorists from some liberation movement no one has heard of are plotting an attack of unprecedented destruction, or a utopian ideology is fermenting in the mind of a cunning fanatic somewhere who will take over a major country and try to impose it everywhere.

Certainly no one could rule out these low-probability/high-impact events, or even begin to estimate their cumulative probability. But acknowledging our ignorance about improbable, trend-defying events is different from denying the existence of the trends. It seems to me that the Long Peace is a genuine trend that clusters with other, more-often-than not, more-or-less successful attempts over the course of human history to contain our violent impulses. 



Steven Pinker is Harvard College Professor of Psychology at Harvard University and the author of The Better Angels of Our Nature: Why Violence Has Declined.

By allandafoe Posted in GT2030