Examining the Typologies of Change in Support for the Civil Union Act and Same-Sex Marriage Over Fourteen Years (2009–2023)

Introduction Given the sustained attacks on LGB+ rights, it is essential to identify how and for whom support for same-sex relationships changes over time. Methods The present study examines distinct growth trajectories of support for the Civil Union Act (2009–2016) and same-sex marriage (2013–2023) across 11 waves of longitudinal panel data ( N = 65,407) spanning 14 years. Results Multi-trajectory latent class growth curve analysis identified three distinct growth trajectories. The high supporter class (68.32%) reported high support for the Civil Union Act and same-sex marriage that (slowly) increased until reaching the ceiling for policy support. The moderate supporter class (17.87%) demonstrated moderate and increasing support for the Civil Union Act and same-sex marriage. Finally, the low supporter class (13.81%) displayed low but increasing support for both legislations. Class membership differed across sexual and religious identification, gender, and age. Those high in conservative ideologies including sexual prejudice, right-wing authoritarianism and hostile sexism were more likely to belong to the moderate and low (compared to high) supporter classes. The moderate and low supporters were also more likely to support—and vote for—conservative political parties. Conclusions We reveal that support for same-sex relationships is increasingly normative and identify the subgroup of the population (most likely) responsible for the ongoing animosity toward LGB+ people. Policy Implications Policymakers should note that threats to undermine LGB+ rights conflict with the majority of the public’s attitudes toward same-sex relationships. We recommend monitoring the low supporter class to protect LGB+ rights and prevent the adoption of anti-democratic norms.