No Kin In The Game: Moral Hazard and War in the U.S. Congress

Abstract

Why do wars occur? We examine the longstanding hypothesis that political elites engage in conflict because they fail to internalize the associated costs. We exploit a natural experiment by comparing the congressional voting behavior of U.S. legislators with draft-age sons versus those with draft-age daughters during the four conscription-era wars of the 20th century, when only men could be drafted. Using panel data, we estimate that having a draft-age son reduces a legislator’s support for pro-conscription bills by 10-17% relative to having a draft-age daughter. Then, using a regression discontinuity design, we estimate that a legislator’s support for conscription increases by a fifth when their son crosses the upper age threshold. We also find that legislators with draft-age sons are more likely to win reelection when the draft is less popular. This is consistent with a political agency model in which voters update their beliefs about politicians’ motives when they make unpopular legislative decisions. Our findings establish that agency problems contribute to political conflict. More generally, we provide new evidence that politicians are influenced by private incentives that are orthogonal to political concerns or ideological references.