Paper short abstract:

By taking advantage of a quasi-natural experimental setting, the 2019 North Korea-United States Hanoi summit, we examine whether Donald Trump's firm and uncompromising posture toward North Korea reassured the Japanese people.

Paper long abstract:

We examine whether a firm and uncompromising posture of a powerful alliance partner reassures people of other member states of the alliance. A common view suggests that allies find their patron state's hardline postures toward their adversaries reassuring, because such postures represent demonstrations of resolve and commitment. In contrast, a few scholars argue that allies consider their patron state's hawkish postures a threat to their security, because such postures raise tensions with their adversaries. Despite the significant implications of these opposing views for theoretical and policy debates, however, empirical evidence is scarce, especially at the mass level.

To address the shortcomings, we statistically test the effect of a powerful alliance partner's hardline posture on reassurance among the public in other member states of the alliance by taking advantage of a quasi-natural experimental setting, the 2019 North Korea-United States Hanoi summit. The Japanese were afraid of the U.S. making significant concessions during denuclearization negotiations with North Korea prior to the summit, but Donald Trump stood firm against Kim Jong-un, which resulted in the negotiations breaking down.

Our analysis of an online survey on a quota sample of the Japanese electorate, conducted before and after the summit, shows that the level of threat perception is significantly lower in the post-summit sample than in the pre-summit one, especially among respondents with a higher level of awareness of international relations.