Despite the substantial body of research on compulsory voting's (CV) relationship with turnout, much remains unknown about the role of different types of CV rules, their enforcement, and their ability to prevent the secular turnout decline observed around the world. Moreover, existing studies that leverage changes to CV laws are limited to a single country. We assemble rich new data on voter turnout and electoral legislation that, we believe, include the most accurate and extensive cross-national measure of CV to date. We test three theoretically derived hypotheses: that CV enforcement matters for participation; that enforcement's effect is conditioned by state capacity; and that, only when CV is enforced, will it mitigate voter turnout's post-1970 tendency to decline. We find support for each. We also find that the nature of sanctions for non-voting is irrelevant for participation.
