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Support for gay marriage reached a new high in the latest ABC News/Washington Post poll, marking a dramatic change in public attitudes on the subject across the past decade. Fifty-eight percent of Americans now say it should be legal for gay and lesbian couples to wed.

That number has grown sharply in ABC News/Washington Post polls, from a low of 32 percent in a 2004 survey of registered voters, advancing to a narrow majority for the first time only two years ago, and now up again to a significant majority for the first time.

See PDF with full results, charts and tables here.

Most Americans, moreover, say the U.S. Constitution should trump state laws on gay marriage, a question now before the U.S. Supreme Court. And - in another fundamental shift - just 24 percent now see homosexuality as a choice, down from 40 percent nearly 20 years ago. It's a view that closely relates to opinions on the legality of same-sex marriage.

See More: Same-Sex Marriage Status in the U.S. By State

Intensity of sentiment about gay marriage also shows considerable change in this poll, produced for ABC by Langer Research Associates. In 2004, strong opponents outnumbered strong supporters by a broad 34 percentage points. Today strong supporters are ascendant, outnumbering strong opponents by 11 points.

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CHANGE - Results of this survey extend evidence of a remarkable transformation in public attitudes. Views on basic social issues often move slowly, if at all. Support for gay marriage, though, has gone from 47 percent to today's 58 percent in just the last three years - culminating a period of change first endorsed by some state courts, then by some political figures, notably with Hillary Clinton expressing support for same-sex marriage today, and Barack Obama doing the same last May, a position he went on to underscore in his second inaugural address in January.

Gay marriage today is legal in nine states and the District of Columbia, and civil unions are legal in eight more states (and were approved last week by the state Legislature in a ninth, Colorado). Thirty-one states ban gay marriage by constitutional amendment.

Related: Individual Americans Explain Why They Changed Their Minds on Gay Marriage

Sharp differences across groups remain, but there have been large advances across the board. In one striking gap, gay marriage is supported by a vast 81 percent of adults younger than 30, compared with just 44 percent of seniors. But that's up by more than 10 points in both groups just since March 2011, and by more than 20 points in both groups since 2004, the low point for gay marriage support in ABC/Post polls.

On the political front, 72 percent of Democrats and 62 percent of independents favor legalizing gay marriage, vs. far fewer Republicans, 34 percent. Still that's up by 18 points among Republicans since 2004, as well as by 24 and 29 points among independents and Democrats, respectively.

Similarly, while just 33 percent of conservatives support gay marriage, that's up by 23 points from nine years ago. Support encompasses more than seven in 10 liberals and moderates alike, with the greatest growth among moderates, 31 points higher now than in 2004.

Sentiment among religious groups shows the same kinds of trends. Among non-evangelical white Protestants, 70 percent in this poll support gay marriage, compared with fewer than half as many of those who describe themselves as evangelicals, 31 percent. But that's up by a nearly identical 25 and 24 points among these groups, respectively, since 2004. Support for gay marriage also is up, by 19 points, among Catholics, to 59 percent.

CHOICE? - As noted, just 24 percent of Americans now see homosexuality as "something people choose to be," down from 40 percent in an ABC/Post poll in 1994 and 33 percent (among likely voters) in 2004; the rest, 62 percent, instead say it's "just the way they are," up from just fewer than half in 1994.

It matters quite a lot: Among the declining number of people who see homosexuality as a choice, just 29 percent support gay marriage, with nearly seven in 10 opposed. Among those who reject this view, support for same-sex marriage soars to 73 percent.

There's one especially dramatic difference in seeing homosexuality as a choice: Forty-five percent of evangelical white Protestants hold this view, among the most to say so in any group tested; among non-evangelical white Protestants, 13 percent agree, among the fewest. Those are down from 1994 by similar margins - 15 and 18 points, respectively.

CONSTITUTION - The Supreme Court has scheduled hearings on gay marriage next week, including challenges to a vote in California barring gay marriage, and to the federal Defense of Marriage Act, which defines marriage as between a woman and a man, denying married gay and lesbian couples federal benefits given to married heterosexual couples. This poll suggests that the high court is the right place for it: Americans by nearly 2-l, 64-33 percent, say the legality of gay marriage "should be decided for all states on the basis of the U.S. Constitution" rather than by each state making its own law on the issue.

That view, interestingly, is not much impacted by attitudes on the issue itself: Among supporters of gay marriage, 68 percent say the Constitution should rule; among opponents of gay marriage, 62 percent say the same.

Preference for a Constitution-based determination encompasses two-thirds or more of Democrats and independents, liberals and moderates alike; it's lower, but still a majority, among conservatives (56 percent) and Republicans (54 percent).

METHODOLOGY - This ABC News/Washington Post poll was conducted by telephone March 7-10, 2013, among a random national sample of 1,001 adults, including landline and cell-phone-only respondents. Results have a margin of sampling error of 3.5 points, including design effect. Partisan divisions are 33-25-35 percent, Democrats-Republicans-independents.

The survey was produced for ABC News by Langer Research Associates of New York, N.Y., with sampling, data collection and tabulation by Abt-SRBI of New York, N.Y.

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