By showing that mass vengefulness helps democratic leaders bring their nations to war, this wonderful book significantly advances our understanding of how cultural values affect international politics. Its most important contribution is demonstrating that democracies that retain death penalty laws were significant more likely to initiate the use of force than non-death-penalty democracies in the 1945–2001 period. The finding is robust to a variety of control variables and specifications, although skeptics may wonder whether it might be inflated by ethnocentrism, beliefs about the utility of violence, or other unmeasured potential covariates.

Rachel Stein attributes the belligerence of death penalty states to cross-national differences in vengeful cultures, on the grounds that citizens’ vengefulness predicts both cross-sectional support for the death penalty and cross-national differences in the penalty’s retention. Her rigorous analysis greatly strengthens the case that the unusual bellicosity of retributivists, observed by Stein and other researchers, affects actual interstate conflict.

A second major argument in Vengeful Citizens, Violent States is that democratic leaders must rhetorically frame interventions as just punishment to mobilize retributivists’ support. Earlier work found that vengeful belligerence is heightened by details about harm done and decreases once enemies such as Saddam Hussein have been toppled. Here, Stein provides new evidence showing that retributivists were disproportionately likely to favor killing Osama bin Laden, retaliating for a hypothetical terror attack on the United States, and punishing attacks on third countries, but they were not particularly hawkish on using force for nonpunitive goals, such as spreading democracy, protecting oil supplies, or defending states that had provoked a fight.

In addition, Stein shows that death penalty attitudes were uncorrelated with U.S. public support for the 1999 Kosovo War, which Bill Clinton initially portrayed as halting fighting among jointly culpable parties, in contrast to the 2003 Iraq War, which George W. Bush portrayed as necessary to topple an evil despot. Careful content analyses of the two presidents’ public statements demonstrate how differently they described the two conflicts.

Stein’s findings on killing Bin Laden and retaliating against terrorists indicate that mass vengefulness is likely to affect support for military retaliation. But in deriving her international conflict hypothesis, Stein argues that vengefulness affects only conflict initiation, on the grounds that even nonvengeful citizens will generally support retaliation in self-defense (p. 62). Further research should explore this apparent contradiction.

Stein’s book should encourage further work on questions that it skirts, including elite and leader vengefulness, connections between revenge and anger, and the rationality of revenge. Stein views revenge as a desire to achieve “a just world” in which “those who inflict suffering on others will be made to suffer in return”; it is thus neither aimed at national interests nor “an immoral, irrational, or pathological impulse” (p. 167). Devotees of the cost-benefit model of public opinion, however, will probably argue that avenging international transgressions often enhances security, and thus is often prudential. On the other hand, revenge’s close connection to the emotion of anger, which is known to bias appraisals of risk and blame, might make revenge a more irrational factor than Stein acknowledges. For example, U.S. public belligerence toward Iraq jumped right after the September 11, 2001 attacks, before President Bush began implying Iraqi complicity and reminding the public how evil Saddam Hussein was. Moreover, many Americans who doubted that Iraq was involved nevertheless felt that invading Iraq would somehow “avenge” the attacks. Sometimes, it seems, revenge may be more “wild justice” than means to a just world.