Over the last decade, support for legalizing same-sex marriage has grown 22-percentage points to majority (54 percent) support. Going somewhat against traditional thought, much of this growth has come from religious Americans who have changed their minds on the issue.

One quarter more Catholics (25 percent) and white mainline Protestants (26 percent) favor legalizing same-sex marriage than they did in 2003. This increase means majorities of both religious traditions now support same-sex marriage—60 percent of Catholics and 62 percent of white mainline Protestants.

White evangelical Protestants, a notably conservative group, have doubled their support for same-sex marriage—12 percent in 2003 to 28 percent in 2014—although there is still minority support within the group. Additionally, more black Protestants now support same-sex marriage than they did one decade ago—23 percent in 2003 to 38 percent in 2014.

At 65 percent, the religiously unaffiliated already showed substantial support in 2003 for allowing gay and lesbian couples to marry legally. Support grew to 77 percent in 2014 among this group.

For more public opinion on same-sex marriage, see PRRI’s “Everything You Need to Know about Same-sex Marriage for the Upcoming SCOTUS Case.”