They came here from non-swing states, same as nearly 1,000 other volunteers milling about the America Coming Together staging area, a tent in a shopping center parking lot.

Dana Perlman and Steve Bauer Feind arrived by plane from Los Angeles on Saturday morning, an hour before the weekend's big door-to-door voter mobilization was to begin. Christopher Labonte arrived Thursday from Washington, D.C. Julian High came from there on Tuesday.

The four volunteers are members or employees of the Human Rights Campaign (HRC), the nation's largest gay, bisexual and transgender political organization. They were part of the largest get-out-the-vote operation Nevada has ever seen. While the Republicans across town had their own effort underway, the ACT coalition -- independent of, but working for the Democratic ticket -- had amassed a large collection of groups -- from labor unions, veteran and student organizations, and HRC, which has 600,000 members and counting.

HRC sent 30 volunteers to Las Vegas over the weekend and 700 people to eight targeted swing states -- Florida, Minnesota, Nevada, New Hampshire, New Mexico, Ohio, Pennsylvania and Wisconsin. It is spending $6.75 million this election, a record for the group. Its primary mission is to help defeat President Bush, who announced his support in February for an amendment to the Constitution that would ban same-sex marriage, and also to help elect "fair-minded" candidates who are against the proposed marriage amendment.

Among the small group of HRC volunteers here, none had ever done shoe-leather campaign work before. "I'm a little nervous," Perlman, an HRC board member more used to organizing fundraisers than ringing doorbells, said as he looked around the staging area.

Groups of four or five people were huddled all over the parking lot, rehearsing scripts to encourage registered voters to vote for Democrats on Tuesday. Inside the tent, volunteers were handing out lunch packs and bottles of water. Dozens of white vans were idling, waiting to transport seven volunteers apiece to neighborhoods across Las Vegas. Volunteers, in their walk-a-thon-comfortable clothes and shoes, studied folders with voter information and advice, such as to remind voters to take identification with them to polling places in case they were challenged by poll watchers.

There is probably not a single political group or community in the country that does not consider this presidential election one of the most crucial elections in memory, if not the most. For the gay community, which makes up about 5 percent of the electorate, Bush's support of the marriage amendment, which helped spawn some of the 11 state initiatives up for a vote on Tuesday that would ban same-sex marriage, has proved a potent galvanizing force. Polls show that most of those amendments are likely to pass.

"I've been at HRC for five years, and I've never seen this kind of passion and energy," said Labonte, a lobbyist.

Along with its voter mobilization effort, which included identifying and contacting not only gay voters but also their allies -- friends and family members -- HRC tracked its political might, matching its members with people who have contributed to campaigns. It found that as of June, HRC members had donated $22 million this year. Membership is rising, up by 25 percent since 2000.

Joe Reubens, a veteran of political campaigns, was hired by HRC as its Nevada field director four months ago. "I'm a straight man who joined the campaign because I'm offended that this man who ran as a 'uniter, not a divider' has proposed an amendment to the Constitution to protect his voting base at the expense of a demographic group," he said. "And from my experience, in this election cycle, many people feel the same way."

Whether Nevadans agree, no one here could say. Bush beat Vice President Al Gore in Nevada in 2000 by four percentage points, taking its five critical electoral votes. Most recent state polls show the race close, but with a slight edge for Bush.

Las Vegas is in Clark County, where 70 percent of Nevada's approximately 1 million registered voters are based. Half the 800,000 people expected to vote, including more than 200,000 in Clark County, have voted in the two-week early-voting period that ended Friday, setting records for the county and the state.

On Saturday, Tom Ellsworth, an ACT volunteer from Oakland, Calif., who served as the team leader and van driver for the HRC group, warned that many people on their lists might have already voted. He also mentioned another on-the-job frustration: Many people wouldn't be home.

Perlman, a Los Angeles lawyer specializing in business litigation, walked an isolated development of peach-colored stucco houses near Nellis Air Force Base, exhilarated at every voter contact he made. He and his partner are large donors to many organizations and campaigns, he said -- raising money this year for the reelection of Sen. Barbara Boxer (D-Calif.), among others -- but have never been foot soldiers.

"I really felt like I needed to see on a personal level what it was like to get out the vote and to connect with people on a one-on-one basis," Perlman said, explaining why he flew, on his own dime, to canvass for the first time. "But the biggest reason? I just couldn't imagine sitting at home this weekend and not rolling up my sleeves and doing everything I could to help win this election."