Long central to nation- and state-building, compulsory military service is again in focus amid rising geopolitical tensions, reviving questions about its broader consequences. We construct a novel global database of conscription reforms spanning 78 countries, linked to harmonized census and survey microdata across six decades. Comparing adjacent birth cohorts who were just drafted versus just exempt, we find that conscription increases men's educational attainment, asset ownership, occupational status, and geographic mobility. Skills acquired during service facilitate these gains. Men's economic returns, in turn, extend to women and children through the marriage market, leading to intergenerational effects. Nation-building effects are mixed: conscription fosters patriotism and interethnic integration, especially when introduced at independence or in diverse societies, but some countries see increased anti-immigrant sentiment. Economic and political benefits are positively correlated but vary systematically with labor-market frictions. Our findings reopen the debate on whether conscription can serve as a tool for inclusive development. (with Siddharth George and Kewei Zhang).