A Threat Next Door? Causal Evidence that Russia's Invasion Increased Willingness to Fight in the Czech Republic but Not in Uruguay

Russia's invasion of Ukraine in February 2022 marked a turning point in European security politics. In this context, the population's willingness to fight is often interpreted as an indicator of societal inclination toward military self-defense and a precondition for strengthening defensive capacities. Yet, causal evidence on what shapes this willingness remains limited, and studies on the effects of Russia's invasion on public attitudes have been largely confined to European countries. I employ Russia's invasion within an unexpected event during survey design to estimate its impact on respondents' willingness to fight for their own country. Drawing on data from the World Values Survey in the Czech Republic and Uruguay, the analysis reveals a significant increase in willingness to fight among Czech respondents -- a country geographically and historically proximate to Russia -- but no comparable effect in Uruguay. These findings offer novel causal evidence that proximate interstate conflict can increase willingness to fight for one's country, which contributes to broader debates on conscription and military security.