Theories of international relations have often incorporated assumptions about time horizons-a metaphor for how heavily actors value the future relative to the present. However, they have not built on a growing body of experimental research that studies how human beings actually make intertemporal tradeoffs. In this article, we present relevant findings from psychology and behavioral economics, notably those of "construal level theory" (CLT), and explore these findings' implications for three classic questions-international cooperation, preventive war, and coercion. We argue that experimental evidence regarding how people discount future value and construe future events challenges the conventional wisdom on international cooperation. We further maintain that CLT helps explain a longstanding puzzle about preventive wars-namely why they are often initiated too late by declining powers but too soon by rising competitors. Finally, we rely on these findings to explain who wins coercive contests and why compellence is often, but not always, harder than deterrence. Scholars of international relations often embed in their theories crucial assumptions about time horizons, and this article seeks to show what differences it makes if we ground these assumptions in what we know about actual human decision making.