Support for Gay Marriage Reaches a Milestone More than half of Americans say gay marriage should be legal.

March 18, 2011 -- More than half of Americans say it should be legal for gays and lesbians to marry, a first in nearly a decade of polls by ABC News and The Washington Post.

This milestone result caps a dramatic, long-term shift in public attitudes. From a low of 32 percent in a 2004 survey of registered voters, support for gay marriage has grown to 53 percent today. Forty-four percent are opposed, down 18 points from that 2004 survey.

The issue remains divisive; as many adults "strongly" oppose gay marriage as strongly support it, and opposition rises to more than 2-1 among Republicans and conservatives and 3-1 among evangelical white Protestants, a core conservative group. But opposition to gay marriage has weakened in these groups from its levels a few years ago, and support has grown sharply among others – notably, among Catholics, political moderates, people in their 30s and 40s and men.

The results reflect a changing albeit still polarized climate. Gay marriage has been legalized in five states and the District of Columbia, by court ruling or legislative action, since 2003, while many other states prohibit it. The Obama administration late last month said it would no longer defend the constitutionality of the Defense of Marriage Act, a 1996 law banning federal recognition of gay marriages.

GROUPS – While younger adults and liberals remain at the forefront of support for gay marriage, the new results underscore its expansion. In an ABC/Post poll five and a half years ago, for example, under-30s were the sole age group to give majority support to gay marriage, at 57 percent. Today it's 68 percent in that group – but also 65 percent among people in their 30s, up a remarkable 23 points from the 2005 level; and 52 percent among those in their 40s, up 17 points.

Adults 50 and older remain more skeptical, but even that's seen change. Most notably, 33 percent of seniors now say gay marriage should be legal, up from 18 percent five years ago.

Trends among other groups are equally striking. Compared with five years ago support for gay marriage has grown by 10 points among women, but by 18 points among men; it's now at parity. Support has grown by 17 points among Democrats, but also by 13 points among independents, to a clear majority, 58 percent, in the crucial political center. And it's 63 percent among moderates, up 21 points.

The poll has an insufficient sample size to evaluate individual racial minority groups reliably. However, support for gay marriage is essentially identical among whites, 53 percent, and nonwhites, 54 percent. That's up by 13 points among whites – and by 20 among nonwhites.

Support is up by a striking 23 points among white Catholics, often a swing group and one that's been ready, in many cases, to disregard church positions on political or social issues. But they have company: Fifty-seven percent of non-evangelical white Protestants now also support gay marriage, up 16 points from its level five years ago. Evangelicals, as noted, remain very broadly opposed. But even in their ranks, support for gay marriage is up by a double-digit margin.

METHODOLOGY – This ABC News/Washington Post poll was conducted by telephone March 10-13, 2011, among a random national sample of 1,005 adults, including landline and cell-phone-only respondents. The results from the full survey have a 3.5-point error margin. The survey was produced for ABC News by Langer Research Associates of New York, with sampling, data collection and tabulation by TNS of Horsham, PA.

For full methodology and questionaire, click HERE.