The Supreme Court on March 27 hears the second of two important same-sex marriage cases — a challenge to the 1996 Defense of Marriage Act (DOMA) that bars the federal government from recognizing same-sex marriage. (See our analysis of the case).

The general rise in public support for allowing gays and lesbians to marry legally has been accompanied by shifting attitudes about how they relate to Americans’ concept of family. In 2003, a 56% majority of Americans agreed with the statement: “Allowing gays and lesbians to legally marry would undermine the traditional American family.” Today, 46% say this.

Partisan differences are substantial, and have grown in recent years. Just a third (33%) of Democrats now agree with the statement, while 63% disagree; in 2003, Democrats were evenly divided on this question. Republican opinions, in contrast, have remained more stable: 68% of Republicans say same-sex marriage would negatively impact the American family, little changed since 2003.

These partisan differences, both in current size and in trajectory, are similar to those seen in attitudes about same-sex marriage. Democratic and independent support for gay marriage has steadily increased over the last decade, while there has not been a commensurate shift in GOP opinion. Read more

Bruce Drake  is a former senior editor at Pew Research Center.