When Kamala D. Harris and Mike Pence face off in the vice-presidential debate tonight, they’re likely to discuss foreign policy.

This was an important topic at the vice-presidential debate in 1984. Then, Geraldine Ferraro — the first and until now the only female Democratic vice-presidential candidate — was asked by one of the moderators, “Do you think in any way that the Soviets might be tempted to try and take advantage of you simply because you are a woman?” Polls taken in 2008, 2018, and 2020 show many Americans still believe men are better equipped than women to handle national security. That matters.

In a paper recently published in International Organization, we find a female president could face political pressure to act “tough” during international military crises and to adopt relatively hawkish foreign policies. That’s simply to combat the gender stereotype that women are less capable of handling foreign policy issues than men.

Here’s how we did our research.

In September 2019, we fielded a survey experiment on a nationally representative sample of 2,342 Americans recruited through Time-Sharing Experiments for the Social Sciences (TESS). Our goal was to estimate two types of public opinion costs that scholars Joshua Kertzer and Ryan Brutger show can affect how leaders conduct foreign policy.

The first type are called “inconsistency costs.” These are the domestic political punishments leaders pay for making a threat against a foreign adversary and then subsequently backing down. For example, Barack Obama paid a political price for not enforcing his “red line” threat after Syria used chemical weapons. Higher inconsistency costs can affect foreign policy by giving presidents political incentives to actually carry out threats, even if doing so isn’t in the national interest.

The second type are called “belligerence costs.” These are the political punishments leaders incur for making threats in the first place. For example, voters largely disapproved of President Trump’s alarming threat to unleash “fire and fury” on North Korea, a nuclear-armed country. Higher belligerence costs — meaning leaders are punished more or rewarded less for making threats — can affect foreign policy by discouraging leaders from making threats in the first place.

To estimate these costs, we first presented all participants with a commonly used hypothetical international crisis in which a foreign country sends its military to take over a neighboring country. We then randomly assigned whether the U.S. president was male (Eric/Steven Smith) or female (Erica/Stephanie Smith) and Democratic or Republican.

We then randomly assigned respondents to read one of three different scenarios for how he or she responds to the international crisis. The president either promises to stay out of the conflict and does so; threatens to send troops to resolve the crisis but fails to actually send troops (inconsistency), or threatens to send troops and follows through (belligerence).

Finally, we asked respondents to what extent they approved or disapproved of the president’s handling of the crisis. Here’s what we found.

1. Female leaders are punished more for backing down from threats than male leaders.

A female president who acted inconsistently by making a threat and then backing down faced about 20 percentage points more disapproval than a male president who acted the exact same way.

Why? The most likely answer lies in gender stereotypes. While Americans believe women are better able than men to handle policy areas like health care and education, they see women as less able to handle national security. Consequently, when a woman backs down from a threat made against a foreign foe, she confirms the public’s suspicion that women aren’t “fit” for the role of commander-in-chief and incurs punishment from the American public.

2. Female leaders are punished less for making threats in the first place than male leaders.

Female presidents are also punished about 14 percentage points less than male leaders for making threats in the first place. In other words, women not only have political incentives to carry out any threats they make, but to make threats in the first place to prove their toughness.

3. Different costs for female leaders have both advantages and disadvantages in crises.

In terms of disadvantages, higher inconsistency costs mean a female president will find it politically more difficult to back down from threats, which could make it harder to de-escalate crises. Lower belligerence costs also mean women have incentives to initiate conflicts.

However, there also potential advantages. If foreign leaders understand the domestic political incentives female leaders face, a female president’s threats will be more credible to foreign enemies, precisely because she is less likely to back down. This means women may actually be more effective at coercing foreign adversaries than men.

Many prominent scholars and policymakers believe more female leadership will lead to peace because women are biologically inclined toward peace and socialized to avoid aggression. Our research suggests more female leadership around the world could have a pacifying effect, but for a different reason. Enhanced threat credibility could allow female leaders to deter foreign countries from initiating disputes in the first place or compel foreign countries to back down once crises begin but before threats escalate to violence.

Iron ladies rather than peacemakers

Research by political scientists Madison Schramm and Alexandra Stark finds, in the real world, female leaders are indeed under pressure to be hawkish to prove they’re tough and competent in foreign affairs.

Prominent female leaders like Margaret Thatcher from the United Kingdom, Golda Meir from Israel, Indira Gandhi from India, and Tansu Çiller from Turkey were often described as “iron ladies” because of their tough foreign policies. In the United States, high-ranking female foreign policymakers like Madeleine Albright, Jeane Kirkpatrick, Condoleezza Rice and Hillary Clinton often advocated more aggressive foreign policies than their male counterparts.

Of course, a President Harris — or any future female president — wouldn’t necessarily follow this pattern. But she would face different political incentives in national security crises than her male predecessors.

Joshua A. Schwartz (@JoshuaASchwartz) is a PhD candidate in political science at the University of Pennsylvania.

Christopher W. Blair (@Chris_W_Blair) is a PhD candidate in political science at the University of Pennsylvania.