It is no wonder that the evolution of democracy is wrought with struggle. Extending the franchise dilutes the power of those whose interests already hold sway over political leaders. This is why the right to vote for different groups, including women has been an uphill battle—women’s interests would become important to political leaders. It is precisely this point that Joselyn Barnhart and Robert Trager make in The Suffragist Peace: How Women Shape the Politics of War. As women gained the right to vote, they became a key constituency for political leaders. In particular, women’s preferences about war became important to leaders. As the authors show, women’s preferences for peace, compared to men, are remarkably consistent over time and space. This means that with suffrage, political leaders, when considering escalating a crisis or going to war, consider women’s pacific preferences when making these decisions.

This book joins the chorus of manuscripts that show how women matter in international politics. The argument is directly and succinctly stated on page 161—“with new voters came new preferences and different policies followed.” The argument is concise but has enormous consequences for international relations. It means that it becomes important to understand how world leaders view women at home, and it means that we must investigate how such women are perceived by leaders. Indeed, the book shows that how leaders interpret and how they view women’s preferences holds important insight into how they make decisions. While scholars have been arguing about the importance of “seeing women” in international relations for decades, Barnhart and Trager show that women’s roles are not just important for international relations broadly, but that women and their viewpoints are important to leaders.

The odds are stacked against Barnhart and Trager in trying to demonstrate evidence for their argument because so much evidence points to war after suffrage was granted. After all, WWII started after much of Europe and the US granted suffrage to women. Many states in the US had granted the franchise to women prior to the start of WWI. If their theory were correct, then war ought to have been prevented in these cases. As they point out themselves, the reader would be “skeptical about some of the core concepts explored in the book” (p. xiv).

Despite these negative cases of WWI and WWII, where war broke out “after” suffrage, Barnhart and Trager demonstrate how the peaceful preferences of women were taken into account during the events that led up to both World Wars. Chapter 5 provides in-depth process tracing of how women’s preferences for peace in the US led them to vote for Woodrow Wilson, the clear pacifist candidate in the 1916 election. Barnhart and Trager show that Wilson’s campaign targeted women (especially in the West) whom the thought would be more amenable to his pacifism (p. 91). Thus, even though the US eventually entered the war, women were key to keeping the US out of the war for a longer period of time. Barnhart and Trager also trace how women in Great Britain helped support Neville Chamberlain’s 1938 Munich Agreement. The authors conclude that “Chamberlain’s belief in women’s support might have given him the push he needed to compromise with Hitler in 1938.” (p. 103). Thus, even though suffrage did not prevent the Great Wars, Barnhart and Trager show how women’s pacific interests as a voting block did influence the decisions of leaders during the time. The detailed historical accounts provided in the chapter shine a light on a missing part of history. Without an account of women influence on leader’s decisions about major world events, history is incomplete.

Other chapters also provide evidence for this. Chapter 3 explores whether and why women’s preferences for peace is stronger than men’s preference for peace (the gender gap). It concludes that “women are less likely to engage in interpersonal aggression and are less likely to support the use of military force against other nations in wars of choice. This is true across countries, across time, and—except when humanitarian needs or immediate self-defense concerns eclipse other rationales for conflict—across all forms of international crisis.” (pp. 64–65). The authors engage in important quantitative empirical work by conducting a meta-analysis of the gender gap in public opinion. This is how they can state with high confidence that the gender gap is real over time and across space. Chapter 4 looks at the cross-national, time series evidence for suffrage, democracy, and war. The authors find that compared to two democracies with suffrage, two democracies without suffrage are 3.2 times more likely to engage in a military dispute. Thus, one could say that they qualify the “democratic peace theory,” suggesting that the granting of suffrage in democracies is what matters for preventing wars.

The authors acknowledge that there are flaws in their argument, but do not always address them. There are perhaps three overarching areas where more nuances would have been helpful. First, the authors homogenize women. The homogenization of women is a problem for all public opinion work, but it is important to state that not all women are the same. The preferences of women vary quite a bit based on identity and differing life experiences. As such, the manuscript would have benefitted from an acknowledgment of intersectionality or the effect of cross-cutting identities such as race, gender, immigration status, sexual orientation, education, socioeconomic status, etc. on preferences formation and influence. This discussion seems especially important because leaders are unlikely to listen to all women in the same way. In the U.S./European context, politicians are most likely to listen to (wealthy) cis-white women. Their preferences are often privileged when compared to women who do not meet that identity because of racism and other forms of structural inequality. A refined argument might suggest that only when particular subgroups of women are peaceful, might leaders take notice.

This omission is particularly noticeable given the focus of the manuscript on the US/Europe, where identity cleavages play a major role in politics. Indeed, a second criticism of the book is the narrow focus on the US/Europe. While the authors include vignettes about Israel, Liberia, and Japan, they are highly stylized and lack the same nuance as the case studies on the US/Europe. Addressing global application of the theory is especially important because some authors have found that the gender gap is nonexistent in some countries (e.g., some Middle Eastern countries). In other words, men and women do not differ in their views about wars in some countries. Thus, an exploration of contextual differences across time and space would make the book stronger and provide stronger evidence of the generalizability of the argument.

The chapter that includes Israel, Liberia, and Japan tell a story about women’s movements for peace in those countries. In doing so, the authors make a different argument that the overarching argument of the book. They show how women’s peace movements are important for agenda setting, but what stands out is that these were autonomous peace movements and women’s franchise was not necessarily a part of the story for their success. Barnhart and Trager make the case that these women’s movements for peace were taken seriously because women were a constituency, but there are examples in history when women did not have the right to vote that women’s autonomous movements for peace made a difference to leaders (e.g., the American Julia Ward Howe called for a Mother’s Peace Day celebrated in 1873 and Gabrielle Wiesniewska founded the Alliance universelle des femmes pour la paix et pour le désarmement). It remains unclear whether these peace movements, prior to suffrage, were effective. Exploring the “interaction” between women’s peace movements and suffrage in more detail would help the reader understand the weight of their dependency.

Third, the authors do not adequately address the barriers to voting. If it is “who votes that matters” (p. 160), then it is important to acknowledge the factors that help or hinder who does get to vote. There are many barriers to women’s ability to vote despite having the right to vote. Women who care for children, and/or who engage in other forms of work may not have time to vote. Women may not be allowed to vote due to violence at home. The authors could have highlighted some of these challenges and addressed how to overcome barriers for women. Relatedly, it would have been helpful to see a discussion about why women hold more peaceful views despite being married. Some people (including politicians) assume that women vote the same way as their husbands (or that husbands prevent women from voting), so does the institution of marriage take away women’s voice and influence? (see Rebecca Traister, All the Single Ladies: Unmarried Women and the Rise of an Independent Nation, 2016).

Finally, the authors don’t always contextualize the argument within the vast international relations and gender literature. Scholars have been making the argument that women matter to international politics for decades. Moreover, there are over 100 articles that show a correlation between women’s inclusion or women’s status in a society and peace within and between countries (see Sabrina Karim and Daniel Hill Jr., Positioning Women in Conflict Studies: How Women’s Status Affects Political Violence, 2024). Some of this work is cited, many are not. Situating the book within this literature would have helped us to better understand the unique contribution that this book makes.

Criticisms aside, Barnhart and Trager help us understand why suffrage was such a hard-earned right and took so long: It is because women hold the power to influence leaders in matters related to war and peace. As a result, we can grasp that reducing barriers to franchise for all groups of people is an important way to ensure peace in the world.