This chapter shifts away from the informational problems that are the focus of the earlier chapters and analyzes the second main rationalist explanation for war, the inability of countries to make binding agreements combined with future incentives to renege on agreements; in short, commitment problems. It begins by analyzing the classic commitment problem of exogenous shifting power, whereby one country is growing more powerful over time. It then analyzes shifting power under incomplete information, and the new issue of reassurance signaling, where the goal is to credibly signal compatible interests rather than strength. It then analyzes the commitment problems present when countries negotiate over issues that affect future military power, such as strategically valuable territory. The chapter then analyzes how a prominent credible signaling mechanism, military mobilization, can induce commitment problems by causing a power shift during a crisis. Finally, the analysis shows how issue indivisibility and risk-acceptant leader preferences can be conceptualized as commitment problems. The exercises ask the reader to analyze many different aspects of commitment problems.