The democratic peace or the observation that no two democratic states appear to have waged wars against each other has spawned a wealth of research in recent years. The first wave of research debated whether the empirical finding was correct and advanced tentative explanations of why democracies might be able to avoid war. These two books represent a second wave of research that takes a more comprehensive look at linkages between domestic political institutions and international behavior. Here, the democratic peace finding itself is taken for granted, and researchers instead focus on the broader implications of theories relating democratic institutions to peace. Both books seek to go beyond the two dichotomies that guided much of the first wave of democratic peace research: the war–peace dichotomy in the case of Paul Huth and Todd Allee, and the democracy–autocracy dichotomy in the case of Norrin Ripsman.

Huth and Allee's theoretical point of departure remains close to existing theories of democracy and peace, but the way the authors attempt to test these theories sets this book apart from earlier work. Instead of focusing on all dyads or pairs of states that may or may not go to war, they argue that more may be learned about linkages between democracy and conflict or peace by focusing on interactions between challengers and defenders to territorial disputes. Rather than a war–peace dichotomy, the authors examine how regime type influences a wider range of conflict behavior by looking at patterns of escalation and negotiations between the parties. They identify three different explanations of conflict behavior based on political accountability, political norms, and political affinity, and then test predictions from the different explanations on three possible stages of a conflict: a) decisions to challenge the status quo; b) offering concessions in negotiations; and c) escalation to the use of force.

Their results suggest that political institutions indeed help account for conflict behavior, in particular in areas where features of traditional theories of international politics, such as power and military alliances, do not display much explanatory power. For example, the balance of capabilities seems a good predictor of when states will threaten to use force to challenge the status quo, but gives few insights as to when countries initiate negotiations or offer territorial concessions. Political institutions play an important role here, as democracies appear to be highly sensitive to the electoral cycle in managing territorial disputes. Consistent with theories stressing accountability, leaders in democracies prefer to initiate negotiations and offer concessions shortly after elections, and diplomacy becomes less likely the weaker an executive's position in the legislature. Moreover, democracies capitalize on the opportunity to reach negotiated outcomes when a democratic adversary is in a relatively secure position domestically. However, democracies only engage in negotiations or make concessions if they believe that these efforts are likely to be met with some success, and they do not hesitate to stand firm if they do not expect such efforts to be reciprocated. Indeed, the authors argue that democracy confers an advantage by allowing leaders to better signal resolve when dealing with nondemocracies. Finally, they find some evidence of monadic effects, as democratic leaders are less likely to initiate force against adversaries, irrespective of their regime type.

Huth and Allee's book is an impressive effort to tailor research design and data collection more closely to the hypotheses of interest. Disaggregating interactions in territorial disputes allows the authors to reach new findings about leaders' ability to substitute other policy options for the use of military force and how regime type influences this. However, although the authors' decisions on research design contribute to this book's strength, they also entail some limitations. All the analyses are carried out on a sample of states with outstanding territorial claims, and many readers will wonder whether the factors considered could not also conceivably influence the likelihood that states will develop territorial disputes in the first place. Despite their general emphasis on accountability, the authors claim to find striking evidence of political norms in that almost no pair of democracies in their sample escalate disputes to the use of force, but instead settle by other means. If this is the case, then one wonders whether democracies may not also be more likely to avoid getting into territorial disputes by making public claims. If so, the most peaceful relations between democracies would be absent from the authors' sample, and much of the interesting effects of democracy cannot be assessed from the data. To say something about this, we would need a supersample of potential issues over which conflict might arise, such as shared water resources. Moreover, territorial disputes are only one type of disputes, and it would be interesting to see additional discussion about the extent to which the authors' inferences may apply to other forms of international behavior and contentious issues.

Ripsman holds that although domestic politics and institutions matter, the democracy–autocracy dichotomy alone is ill suited to capture the relevant differences. Both democracies and autocracies can be constrained, but the relevant question is whether some institutional features and practices afford an executive more or less autonomy or ability to act upon its preferences in the face of political opposition. Ripsman relates structural autonomy both to formal institutions and informal decision-making procedures and norms, and he examines how structural autonomy influences a leader's ability to normalize relations with defeated adversaries. International relations theorists have argued that states often find it difficult to resist popular pressure after wars, even though a vindictive peace will make it more difficult to avoid future conflict. The argument is tested on the peacemaking policies with Germany of France, the United Kingdom, and the United States after World War I and II. Ripsman argues that although leaders in structurally constrained states such as the French Fourth Republic have little leeway in avoiding vindictive policies that they believe to be unfortunate, democracies do not generally follow poor peace-making policies. The more autonomous leaders in Britain and the United States were able to effectively rebuild and rearm Germany to counteract the new Soviet threat after World War II, despite widespread popular resistance.

Ripsman's book succeeds in demonstrating that democracies should not be regarded as a monolithic bloc inasmuch as they display considerable variation in their foreign policies. The author cleverly demonstrates how various perspectives on institutions and behavior may all be correct but apply under different circumstances, depending on the executive's structural autonomy. Moreover, he highlights the importance of informal institutions such as party discipline for foreign policy behavior. Cognizant of the problems of classifying autonomy on the basis of the foreign policy decisions to be explained, he makes great efforts to classify structural autonomy from ex ante identifiable characteristics, although the qualitative way in which these features are identified is somewhat case specific and less transparent than I would have preferred.

Perhaps the greatest problem in Ripsman's empirical test is the relative lack of variance among the cases. As the author concedes, it is difficult to disentangle the role of structural autonomy from the intensity of public opinion. He argues that public opinion cannot account for variation in the peace-making policies, since public opinion was consistently anti-German in all the three states. I am not persuaded that this is a good test of the salience of issues between countries, and a more comprehensive test of the structural autonomy thesis should compare between cases with more easily identifiable differences in public opinion and issue salience. Moreover, since all the cases examined are liberal democracies, this analysis tells us little about structural autonomy among autocracies and whether the variance in structural autonomy within democracies is large relative to autocratic regimes. Finally, Ripsman holds that state autonomy is issue specific, and notes that his approach to classifying state autonomy often yields results at odds with the existing literature on state autonomy, which usually regards France after World War II as a prototypical strong state. Given the importance accorded to informal institutions in this account, it is not clear to me if public opinion can be considered independently of the institutional features held to shape state autonomy, which again raises issues about ex ante identifiability.

Both of these books exemplify the perhaps disproportion-ate amount of attention given to institutional characteristics relative to preferences or public opinion in current research on political institutions and international behavior. Even though the authors argue that public opinion plays an important role in the demand for foreign policies, neither book evaluates its impact in any systematic manner. The accountability concerns identified by Huth and Allee, for example, may allude to how democracies sometimes lack opportunities to use force, but they tell us less about the possible role of the public in altering willingness to use force against some opponents but maybe not others. Data avail-ability has lead many researchers to study the role of institutions divorced from preferences, but without more systematic research on the role of public opinion, we cannot really know whether institutions alone or their interactions with preferences lead to the observed differences in behavior.

My minor reservations notwithstanding, The Democratic Peace and Territorial Conflict in the Twentieth Century and Peacemaking by Democracies are both important contributions to the literature on domestic politics and international behavior, and they deserve a wide audience.