Does the US Really Embolden its Allies? Evidence from a Survey Experiment in Japan

Do patrons’ signals of security commitments embolden junior partners? Scholars and practitioners have considered that supportive gestures by patrons could motivate junior partners to adopt more aggressive postures in their own disputes. While the theoretical logic is compelling when considering states as unitary actors, it is less clear if this logic applies to the domestic public that may have differing interests from leaders. To complement this gap, we conducted a survey experiment in Japan, a close US ally with a territorial dispute with China. We find that US presidential signals increase the credibility of US military intervention in the dispute; however, no evidence of emboldenment effects is found—public support for escalatory policies does not increase accordingly. Additionally, we find that US signals do not encourage the public to punish leaders backing down after announcing aggressive policies. These findings challenge the conventional understanding of an important effect of alliance politics.