The Secular Divide and GAL/TAN Politics: How Religion Shape Same-Sex Union Legislations’ Impact on Attitudes toward Homosexuality in Europe

National contexts have been overlooked by previous comparative studies on the impact of same-sex union (SSU) legislations on public attitudes toward homosexuality. This study examines the role of religion focusing on two aspects: the secular-religious divide and the GAL/TAN political cleavage. Using 2002–2016 European Social Survey from 24 countries, I demonstrate that partnership legislation has more diverging impact in more secular countries, with core church members developing stronger homonegativity. Stronger secular-religious divide in the population and the strength of GAL/TAN political cleavage induce more negative impact for legislation, regardless of individual religiosity or partisanship. The study’s analysis of how national contexts influence the impact of SSU legislations on attitudes sheds light on the influence of secularization changes and political polarization enhancing “moral polarization” in Western societies. However, the resulting backlash mostly occurs among strongly religious people, while others become increasingly liberal.