In the current polarized political climate there is heightened attention paid to the American state constitutional provisions known as “Blaine Amendments” or “No-Aid Provisions” that were passed between 1835 and 1959 to prohibit public aid to religious schools. Judgments about No-Aid Provisions have largely been made by scholars on an ad hoc basis using narrative-based historical accounts, emotive language and without clear classificatory criteria. Using content analysis this article constructs the first quantitative scale of No-Aid Provision strength and subjects it to statistical treatment to explain why some prohibitions are much stronger than others. It finds that larger Catholic populations, Republican dominance, and Federal Enabling Acts make No-Aid language more strident. In so doing this article adjudicates between competing explanations for No-Aid Provision strength in a way that illuminates the interaction of politics, religion and education in America.