War Causes Religiosity: Gravestone Evidence from the Vietnam Draft Lottery

Does war make people more religious? Answers to this classic question are dominated by the lack of causality. We exploit the Vietnam Draft Lottery -- a natural experiment that drafted male U.S. citizens into military service during the Vietnam War -- to conclusively show that war increases religiosity. We measure religiosity via religious imagery on web-scraped photographs of hundreds of thousands of gravestones of deceased U.S. Americans using a tailor-made convolutional neural network. Our analysis provides compelling and robust evidence that war indeed increases religiosity: people who were randomly drafted into war are at least 20 % more likely to have religious gravestones. This effect sets in almost immediately, persists even after 50 years, and generalizes across space and societal strata.