The Washington Post/ABC News poll released yesterday provides additional support for my Sunday Washington Examiner column headlined “Support for same-sex marriage crosses party lines.” The Post/ABC poll shows that 58% of Americans believe it should be legal for gay and lesbian couples to marry and 36% believe it should be illegal. That’s one of the highest poll figures for support of same-sex marriage I’ve seen. The Post/ABC poll also shows partisans of both parties are split. Democrats favor same-sex marriage by 72%-23%; in 2004 they supported it by only 50%-46%. Republicans oppose legal same-sex marriage 59%-34%; in 2004 they opposed it 72%-24%. Independents favor it now 62%-33%; they opposed it in 2004 50%-47%.

If you look at responses to some issues prominent in partisan debate, you find that 80% to 90% of Republicans go one way and 80% to 90% of Democrats go the other. Attitudes on same-sex marriage are more mixed and cross party lines. The Post/ABC poll has one-third of Republicans favoring same-sex marriage (a position I would never have predicted a few years ago) and one-quarter of Democrats opposing it. Politicians tend to dislike cultural issues on which opinion crosses party lines, as was the case with abortion back in the 1970s. They fear losing their party’s voters who disagree with them on the issue and they’re not confident they can win over the other party’s voters who agree with them on the issue. An old politician is supposed to have said, “Some of my friends are for the bill, and some of my friends are against the bill, and I’m always with my friends.” It’s a lot easier when your friends are all on the same side.

Chris Cillizza, proprietor of the Post politics blog The Fix (and a researcher for the Almanac of American Politics of which I’m co-author 15 years ago) has an excellent blogpost  showing how support for same-sex marriage has increased among each generation over time. There remains a huge generational split—deeper than I can recall on any prominent issue—but at least in this poll support for legalizing same-sex marriage is up to 44% among voters 65 and over. That seems somewhat high to me. In National Opinion Research Council poll data which Cillizza cites, the support of legal same-sex marriage among the G.I. Generation (defined as those born from 1928 to 1945, thus those 67 or older) is only 30% now, but it has risen from 23% in 2004 (and was higher than 30% in a 2010 poll) and 9% in 1988.

The NORC data shows that in 1988, support for same-sex marriage was 14% among baby boomers, 12% among the younger Generation Xers and 9% among the Baby Boom generation. A lot of people have changed their minds since then.