Uneven Rainbows: Why EU Member States Adopt or Reject Gay Marriage

This paper explains why there are a rising number of referenda and parliamentary laws approving or rejecting same-sex marriage in Europe since the early 1990s. Adoption or rejection varies according legal tool used—either national legislation or constitutional referenda—and degree of success. In some countries, constitutional referenda were held either to outlaw explicitly same-sex marriage or to permit it. I explain these diverse outcomes by modeling the interaction of transnational LGBT social movements, the political ideology of incumbent governments, and the temporal proximity of national elections. When transnational LGBT-rights movements are weak, incumbent governments are conservative, and they face reelection within a year, constitutional referenda banning same-sex marriage are held and often succeed. When transnational LGBT movements are strong, incumbent governments are leftist, and no election is on the horizon, parliamentary legislation is the chosen methods and succeeds. A quantitative analysis of legislative and referenda outcomes among 28 EU Member States supports this hypothesis. Outcomes are only weakly dependent on the results of gay marriage debates in neighboring countries. This paper contributes to the growing literature on the interaction of transnational social movements and their conditional impact on domestic political change in Europe.