Since the mid-1980s, scholars of international politics have debated whether democratic states are strongly inclined to keep peace with one another. Apart from its academic interest, the "democratic peace" thesis has the greatest possible policy relevance. If democracies are in fact hardwired to treat each other benignly and if we can devise nonviolent means of encouraging democratic rule, we may have finally discovered a recipe for lasting peace.

The idea that democracies do not fight one another is undeniably attractive for those who happen to live in them. It would be wonderful if spreading our preferred form of government were also a reliable means of promoting peace, and one can hardly imagine a stronger justification for exporting republican ideals. Since war between the major democratic powers is extremely unlikely at present, the democratic peace is also intuitively plausible.

Yet the inherent attractiveness of this proposition is precisely why Americans should view it with some caution. Because the idea of a democratic peace is so flattering to our own values, we may embrace it even when the evidence is ambiguous and its long-term validity uncertain. Since many scholarly works have cast doubt on the hypothesis, a healthy sense of skepticism seems warranted.


The latest entrant into this burgeoning debate is Spencer R. Weart. Drawing a critical distinction between "democratic" and "oligarchic" republics, he argues in Never at War that well-established republics of the same type almost never fight one another. Although history offers up a number of near misses and potential exceptions, Weart concludes that none of them seriously damages his basic claim. For Weart, therefore, spreading democracy remains the most promising path to world peace.

Weart's central argument rests on two empirical propositions. First, truly democratic republics -- which he defines as states where at least two-thirds of the citizens enjoy full political rights -- have simply never fought one another. Second, so-called oligarchic republics -- states where less than a third of adult males hold full political rights -- have almost never fought one another. Wars do occur

between democracies and oligarchies and between republics and dictatorships, but they do not occur between republics of the same type. This claim does not apply if a republic is brand new, but Weart argues that it is virtually 100 percent reliable once a republic has been consolidated over at least three years.

For Weart, the key to the "republican peace" lies in a broad conception of political culture. A state's political culture consists of "the beliefs that a group's members hold about how people ideally ought to deal with another, and their beliefs about how people actually do deal with one another in practice, when groups are in conflict." He suggests that tolerance and compromise are central to republican political culture and argues that political elites will apply lessons learned at home to foreign policy. As a result, republican diplomats will prefer negotiated settlements and eschew the use of force, especially when dealing with one another.

Most importantly, Weart believes that republican states "draw the crucial boundary around one's in-group to include everyone, even foreigners, who shares one's political culture." Political culture thus forms the critical dividing line between those who are part of the "in-group" and those outside it. Democratic republics regard other democracies as part of their own "in-group" and reject the use of force against them, but see oligarchies and dictatorships as illegitimate outsiders who do not merit the same restraint. Similarly, while oligarchic republics view democracies as a source of subversive ideas and readily use force against them, they refrain from attacking other oligarchies.

Weart bases these sweeping claims on a survey of the Greek and Italian city-state systems, the Swiss Confederation, the Hanseatic League, and more recent cases such as the American Civil War, the Anglo-Boer War, and World War I. Although his historical treatments are brief and his supporting documentation seems intended more to dazzle than persuade, the pattern of evidence is at least suggestive. Wars between similar types of republics appear to have been relatively rare, and Weart argues that virtually all the apparent exceptions occurred either because the antagonists were not really the same sort of republic or because the level of violence was trivial.

Weart lays out his case in clear, readable prose and livens his narrative with entertaining anecdotes. His distinction between democratic and oligarchic republics and his emphasis on their being "well-established" is a useful qualification to the democratic-peace hypothesis, helping to account for several historical anomalies. Weart also acknowledges that the spread of democratic principles is not an unalloyed good -- both because democracies are prone to using force to export their ideals and because autocrats' fear of democratic rule is itself a potent source of insecurity and conflict. For these reasons, Never at War is in many ways the most accessible and comprehensive brief for the democratic peace available. But by limiting his discussion primarily to evidence that supports the democratic-peace hypothesis, Weart tells only one side of the story.


Critics of the democratic-peace hypothesis make two main counterarguments. Their first line of attack holds that the apparent pacifism between democracies may be a statistical artifact: because democracies have been relatively rare throughout history, the absence of wars between them may be due largely to chance. Evidence for a democratic peace also depends on the time periods one examines and on how one interprets borderline cases like the War of 1812 or the American Civil War. Critics also note that strong statistical support for the proposition is limited to the period after World War II, when both the U.S.-led alliance system and the Soviet threat to Western Europe's democracies discouraged conflict between republics.

A second challenge focuses on the causal logic of the theory itself. Democratic-peace proponents often attribute the absence of war between republics to a sense of tolerance and shared values that makes using force against fellow republics illegitimate. (As noted above, Weart's version of this argument emphasizes the tendency for republics to see similar states as part of their own "in-group.") If this theory is true, however, there should be concrete historical evidence showing that democratic leaders eschewed violence against each other primarily for this reason. But critics like Christopher Layne have shown that when democratic states have come close to war, they have held back for reasons that had more to do with strategic interests than shared political culture. These cases suggest that even if democracies have tended not to fight each other in the past, it is not because they were democracies.

Instead of meeting these challenges head-on, Weart assembles his own body of supporting evidence and devises his own explanation for the apparent lack of war between republics. Although his arguments should not be dismissed lightly, Never at War illustrates many of the limitations that have marred this debate since its inception.

To begin with, Weart's treatment of historical materials is hardly evenhanded. He is quick to embrace evidence that supports his argument and even quicker to reject evidence that challenges it. Thus, he dismisses in a single footnote the claim that the democratic peace may be a statistical artifact and treats the work of other skeptics with equal disdain. He also excludes the various wars between the Roman republic and its neighbors, including the brutal Punic Wars with Carthage, on the grounds that "no primary sources nor reliable secondary sources survive." Yet he does not hesitate to use other ancient sources that buttress his claim, such as Thucydides and Xenophon, even though they are by no means perfectly reliable. Modern classicists generally agree that both Carthage and Rome were oligarchic republics, which suggests that excluding them was a largely arbitrary judgment that just happened to leave Weart's central claim intact.

Second, Weart's historical accounts focus almost entirely on the role of political culture and pay little attention to more plausible alternative explanations. His cases show that political culture might account for the absence of war between similar republics, but he rarely asks whether other factors were more important -- either in keeping the peace between similar republics or in causing wars between states whose domestic regimes were different. As presented, his case studies create the impression that political culture is the key to explaining war and peace, but Weart offers scant direct evidence for this.

Weart's interpretation of Anglo-American relations illustrates this problem nicely. His account of the War of 1812 emphasizes England's "arrogant" and "imperious" maritime policies (including its impressment of U.S. seamen and embargo on trade with France) and highlights the differences in English and American diplomatic styles. This interpretation implies that war occurred because England was an aristocratic republic and the United States a democracy, but it overlooks the fact that England's maritime policies were a direct outgrowth of its protracted war with Napoleonic France. What Weart portrays as a clash of cultures was at bottom a clash of national interests. Similarly, Weart attributes the peaceful resolution of the Venezuelan crisis of 1896 to the growing similarities between the two republics, especially the shared Anglo-American preference for negotiation and compromise. In fact, U.S. statesmen were interested not in compromise but in reaffirming U.S. primacy in the western hemisphere. War was averted not because both sides were republics, but because England lacked the strength to oppose the United States in its own backyard and England's leaders knew it. Weart also sees the subsequent rapprochement between England and the United States as the result of their shared democratic character, but he fails to mention that England was mending fences with imperial Japan and czarist Russia during the same period. A similar political culture may have facilitated the Anglo-American rapprochement, but strategic calculations -- especially the rise of Germany -- were much more important.

Third, Weart's analysis rests on the same sort of arbitrary coding procedures that marred earlier democratic-peace research, and he relies on a number of familiar loopholes whenever a case does not fit his thesis. The most obvious escape hatch is the admission that republics of the same type may fight one another if either side believes that its opponent is not the "right" kind of republic. Thus, Weart explains away the Athenian expedition to Syracuse in 415 B.C. by saying that the republican regime in Syracuse "was probably not perceived by the Athenians as a full democracy" (even though it was actually nearly as democratic as Athens) and accounts for France's 1923 invasion of the Ruhr by noting that past clashes had convinced the French that the Germans were "an innately authoritarian people" (no matter what the Weimar Constitution said). The Anglo-Boer War is similarly excluded on the grounds that the Boers' treatment of the native population allowed the English to portray their opponents as less than fully democratic. But England's leaders were equally willing to deny full political rights to any imperial subjects they regarded as inferior, which suggests that the political cultures of the antagonists were not so very different after all.

These fudges mean that the republican peace depends less on shared political culture than on each side's perception of what the other state is like. If either side has even flimsy grounds for believing that the other does not fully share its political values or has other reasons to fight and simply wants to portray the other side as somehow fundamentally different, Weart's recipe for peace loses most of its power.


Weart does recognize that shared political culture can be an unreliable barrier to war when serious conflicts of interest arise because states will simply use other criteria to exclude rivals from their "in-group." Thus, he acknowledges that religious differences drove the Swiss republics of Lucerne and Bern to war in the seventeenth century. He further admits that republics have had little difficulty justifying imperial expansion against less-developed but essentially democratic societies simply by declaring the victims "ignorant savages" and placing them outside the "civilized" in-group. Similarly, democracies like the United States overthrew freely elected governments in Guatemala and Chile because American suspicion that they might "go communist" was enough to exclude them from the circle of "acceptable" democracies. Weart, however, does not seem to realize how damning these admissions are to his argument and instead relies on ad hoc rationalizations to paper over the holes.

This brings us to a final gap in Weart's case. Even if its historical judgments are accurate, Never at War cannot tell us how republics would behave in a world in which they were the only type of government. Such a world has never existed, of course, and we simply do not know if the historical affinity among democracies would persist without authoritarian states. The struggle between authoritarian and democratic ideals has been a critical fault line for the past two millennia, and it is easy to understand why like-minded regimes have been inclined to cooperate when confronted by states whose ideals posed a direct threat to their own security. But were this basic distinction to evaporate, cleavages between democracies would probably become more salient. One can easily imagine republican states making invidious distinctions among themselves as conflicts of interest grew more acute, particularly if they no longer needed to join forces against monarchs and dictators. At the height of the Cold War, after all, Americans tended to see Japan as a liberal democracy molded largely in their own image. But as soon as Americans began to fear that Japan was overtaking them economically, they began to "discover" that Japanese politics were less liberal than they had previously thought. This episode suggests that if the United States were to face a democracy of roughly equal capabilities, both sides would find ways to place the other outside its own democratic "in-group." Republics may have tended to band together in the past, but a world composed solely of them might employ different criteria to identify friends and foes. Not only is Weart's interpretation of history problematic, its relevance for the future may be quite limited.

Despite its shortcomings, Never at War is a useful contribution to this important debate. Readers who want to make up their own minds will want to compare it with Miriam Elman's recent Paths to Peace and Joanne Gowa's forthcoming Ballots and Bullets. Democracies may or may not fight each other, but these works suggest that the scholarly struggle is far from over.

Some Americans find these academic debates frustrating. But ask yourself which you would prefer: a world where some great powers were democratic and others were not but where the United States was clearly number one, or a world where all the major powers were democracies but the United States was number three, four, or perhaps even lower. Reasonable people can disagree about which world would be preferable, but how you answer this question will tell you which side of the democratic-peace debate you are on.

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  • Stephen M. Walt is Professor of Political Science and Master of the Social Science Collegiate Division at the University of Chicago. His books include The Origins of Alliances.
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