This article develops and tests two competing arguments regarding how a patron’s diplomatic visits influence the military spending of protégés. One argument posits that a patron’s visits will decrease allies’ defense spending by producing reassurance (reassurance hypothesis). Another perspective contends that such visits will increase allies’ burden sharing by fostering allied partnerships (partnership hypothesis). I test these hypotheses by analyzing US presidential visits to allies and the annual percentage changes in allies’ military spending from 1950 to 2007. I find evidence supporting the reassurance hypothesis, indicating that diplomatic visits by US presidents are associated with lower military expenditures by allies the following year. Furthermore, I find that the negative effect is primarily observed when visits are made in the first 3 years of a presidential term, while visits in the final year of a presidency do not result in significant changes in allied burden sharing. The findings highlight the role of a patron’s travel diplomacy in providing reassurance in military alliances, as well as its unintended consequence for protégés’ foreign policy: reduced alliance contribution.