That trade and security are linked is among the oldest claims in political economy. A new paper by Ling Feng, Qiuyue Huang, Zhiyuan Li, and Christopher Meissner marks a major step forward in measuring the peace dividend credibly, and the magnitudes are striking. A doubling of bilateral trade between two countries reduces their probability of militarized conflict by roughly 30 percent. It also softens the perception of enmity that primes conflict in the first place.