Since Massachusetts became the first state to legalize same-sex marriage through court action in 2003, 26 states have passed voter-approved constitutional bans on gay marriage, bringing the total number of states with voter-approved bans to 29. Prior to 2003, only Alaska, Nebraska and Nevada had passed constitutional amendments prohibiting the practice. Only Arizona, in 2006, has rejected a constitutional ban on gay marriage at the ballot box. However, like California and Florida, Arizona passed a ban this year. In addition to these constitutional amendments, legislatures in 42 states have passed laws limiting the legal definition of marriage to a union between a man and a woman. Read More

Russell Heimlich  is a former web developer at Pew Research Center.