No Kin in the Game: Moral Hazard and War in the US Congress

Abstract

Why do wars occur? We exploit a natural experiment to test the longstanding hypothesis that leaders declare war because they fail to internalize the associated costs. We test this moral hazard theory of conflict by compiling data on 9,210 children of 3,693 U.S. legislators who served in Congress during the four conscription-era wars of the 20th century: World War I, World War II, the Korean War, and the Vietnam War. We test for agency problems by comparing the voting behavior of legislators with draft-age sons versus draft-age daughters. We estimate that (i) having a draft-age son reduces legislator support for pro-conscription bills by 10-17%; (ii) support for conscription increases by a quarter as a legislator's son crosses the upper age threshold; and (iii) legislators with draft-age sons are more likely to win reelection when the draft is less popular. These results are consistent with a political agency model in which voters update their beliefs about politicians' motives when they make unpopular legislative decisions. Our findings provide new evidence that agency problems contribute to political violence, and that elected officials can be influenced by changing private incentives.