Rainbow flags and homemade signs dotted the crowds filling Pennsylvania Avenue in front of the White House as people chanted "Hey, Obama, let mama marry mama" and "We're out, we're proud, we won't back down." Many children were also among the protesters. A few counter-protesters had also joined the crowd, which stretched several blocks by the afternoon.
Jason Yanowitz, a 37-year-old computer programmer from Chicago, held his daughter, 5-year-old Amira, on his shoulders. His partner, Annie, had their 2-year-old son, Isiah, in a stroller. Yanowitz said more straight people were turning out to show their support for gay rights.
"If somebody doesn't have equal rights, then none of us are free," he said.
"For all I know, she's gay or he's gay," he added, pointing to his children.
Some participants in the National Equality March woke up energized by Obama's blunt pledge to end the ban on gays serving openly in the military during a speech to the nation's largest gay rights group Saturday night.
The chairman of the Senate Armed Services Committee said Sunday that Congress will need to muster the resolve to change the "don't ask, don't tell policy" - a change that the military may be ready for.
"I think it has to be done in the right way, which is to get a buy-in from the military, which I think is now possible," said Sen. Carl Levin, D-Mich.
Obama's political energies have been focused on two wars, the economic crisis and health care reform, though he pledged "unwavering" commitment even as he wrestled with those problems.
March organizer Cleve Jones, creator of the AIDS Memorial Quilt and a protege of gay rights pioneer Harvey Milk, said he had initially discouraged a rally earlier in the year. But he and others began to worry Obama was backing away from his campaign promises.
"Since we've seen that so many times before, I didn't want it to happen again," he said. "We're not settling. There's no such thing as a fraction of equality."
Unlike the first march in 1979 and others in 1987, 1993 and 2000 that included celebrity performances and drew as many as 500,000 people, Sunday's event was driven by grassroots efforts and was expected to be more low-key. Washington authorities don't disclose crowd estimates at rallies, though at least several thousand appeared to be in attendance.
Also among the crowd were a couple of noteworthy activists: Cynthia Nixon, a cast member from HBO's "Sex and the City" who hopes to marry partner Christine Marinoni next year; and Judy Shepard, who became an advocate for gay rights after her son Matthew was killed because he was gay.
Many marchers were outraged after the passage of California's Proposition 8, which canceled the right of gays to get married in the state.
Kipp Williams, a 27-year-old San Francisco resident, said he moved to California from the South seeking equality but realized after Proposition 8 that gay people are second-class citizens everywhere.
Contrary to the California Supreme Court's decision on the legality of the referendum, he said "there is no exception to the equal protection clause of the 14th Amendment of the Constitution."
Sara Schoonover-Martin, 34, came from Martinsburg, W.Va., with her wife, Nicki, wearing matching veils and pink T-shirts that said "bride" and "I do." The couple eloped at Martha's Vineyard in Massachusetts earlier this year.
"When marriage is legalized in West Virginia, we will renew our vows and have our family and friends there," Sara said. "I'm angry that it hasn't occurred quicker. This affects my life every day, 365 days a year."
For Lt. Dan Choi, the day began with a jog around Washington's memorials, calling cadence at 8 a.m. with fellow veterans and supporters before joining the march. Choi, a West Point graduate, Arabic speaker and Iraq war veteran, is facing discharge under the military's "don't ask, don't tell" policy for revealing in March that he is gay.
He appeared later at a rally, wearing his Army uniform and a piece of black tape over his mouth.
"Many of us have been discharged from the service because we told the truth," he said. "But I know that love is worth it."
Other activists doubted the march would accomplish much. They said the time and money would have been better spent working to persuade voters in Maine and Washington state, where the November ballot will include a measure that would overturn a bill granting same-sex couples many of the benefits of marriage.
A bill introducing same-sex marriage in the nation's capital also was introduced last week by the District of Columbia Council and is expected to easily pass.
Rep. Barney Frank, an openly gay member of Congress, said the marchers should be lobbying their lawmakers. He said the demonstrations are simply "an emotional release" that do little to pressure Congress.
"The only thing they're going to be putting pressure on is the grass," the Massachusetts Democrat said Friday.