The Secular Divide and GAL/TAN Politics: How Religion Shapes 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 polarization. Using 2002–2016 European Social Survey from 24 countries, I demonstrate that legislation has more diverging impact in more secular countries, with core church members developing stronger homonegativity. Stronger secular-religious divides in the population do not posit more negative legislative impact. However, the polarization along the GAL/(green/alternative/libertarian)/TAN(traditionalist/authoritarian/nationalist) political cleavage induces more negative impact for partnership 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 “value polarization” in Western societies. While the backlash associated with secularization mostly occurs among strongly religious people and others become increasingly liberal, the undermining impact of political polarization is present even among the more liberal parts of the population.