Politicians are more likely to support conscription when they don’t have draft-age sons

Do politicians internalize the consequences of their war-related votes? A new paper published in the Journal of Political Economy finds that they do—when their family is involved.

In “No Kin in the Game: Moral Hazard and War in the U.S. Congress,” authors Eoin F. McGuirk, Nathaniel Hilger, and Nicholas Miller compare conscription-related voting records of members of Congress with and without draft-age sons. They find that legislators with sons eligible for the draft are 7-11 percentage points less likely to vote for conscription than their counterparts with daughters of the same age.

The authors compiled a dataset of the 248 roll-call votes pertaining to conscription that were undertaken in the United States House of Representatives and Senate between 1917 and 1974, a period which saw U.S. involvement in World War I, World War II, the Korean War, and the Vietnam War.

The authors established which members of Congress serving during each of those four wars had sons of draftable age, as conscription in this period in American history only applied to men. The lawmakers with sons who could be drafted were more exposed to the direct costs of conscription—their own children perhaps would be affected by the outcome of their legislative votes.

McGuirk, Hilger, and Miller conduct several analyses in the dataset, comparing not only the likelihood of legislators with draft-eligible sons to vote for conscription against the likelihood of legislators with daughters of the same age, but also how legislators with sons above or below the upper age draft eligibility cutoffs voted.

The idea is that a legislator with a son below the cutoff is potentially exposed to the potential costs of conscription, as their son could perhaps be conscripted in the future, while one with a son above the upper age cutoff had no risk of this. The researchers found that this latter group was 18.8 percentage points more likely to vote in favor of conscription than their counterparts with younger sons.

But what are the mechanisms underlying this voting difference: are they simply manifestations of self-interest? Or is it possible that by having a draft-age son, some legislators endeavor to learn more about the social costs of conscription, which then informs their stance? The authors test how voting behavior of a legislator changes as their son ages from eligible to ineligible for the draft. If the latter were true, “we should not detect a change in voting behavior, since this motive ought to persist long after the politician’s own son ages out of eligibility,” they write.

They find that a congressperson is 12.7 percentage points more likely to vote for conscription one year after their son ages out of draft eligibility than they were the year before. “This is unlikely to be caused by a sudden change in preferences or electoral motives,” the authors write. Rather, private incentives are likely at play.

Finally, McGuirk, Hilger, and Miller also test how this voting behavior affects a legislator’s chances of reelection in times when conscription is either popular or unpopular, based on historical accounts of public opinion. For instance, the draft was more popular during wars in the first half of the 20th century and declined in popularity by the second half.

If the draft is popular, senators facing reelection would seem to be more likely to vote in favor of it in order to increase their chances of reelection. The analysis shows that politicians with draft-eligible sons were indeed less likely to win reelection during World War I, while this effect disappears by the Cold War.

Ultimately, the authors write, “Our finding has implications for the broader literature on special interests and quid-pro-quo politics, as we show that legislators respond sharply to changing private incentives, which is an important assumption underlying many of these studies.”