Joel Page / AP Gay-marriage supporters gather Sept. 10, 2012, at a rally outside of City Hall in Portland, Maine.

Updated at 1:45 p.m. ET -- After losing some 30 ballots on same-sex marriage across the country over the past decade, advocates of lesbian and gay couples are encouraged by polls showing they have a good chance of finally logging their first victory in a statewide popular vote.

Polls show majorities back same-sex marriage in Maryland, Washington and Maine, and they indicate a tight battle in Minnesota – the four states holding votes on the issue in November.

“We’re feeling positive. The reality is, we haven’t won a ballot measure on marriage yet,” said Sarah Warbelow, state legislative director for the Human Rights Campaign, an advocacy group for gay, lesbian, bisexual and transgender rights. “I think it’s very reasonable and realistic to expect that we’ll win one or more of these ballot measures; certainly the polling suggests that all four are … a possibility.”

Polling ahead of such ballots has not always accurately captured voters’ sentiment: In California in 2008, the same-sex marriage camp had a majority, though the ban on gay and lesbian marriage ultimately prevailed. In North Carolina, polls had predicted a closer race in the May ballot on the constitutional amendment (a 16-point difference, according to Public Policy Polling at the time), but the anti-gay marriage camp won by more than 20 points.

“They’re doing what they’ve always done, taking their victory lap before their first victory,” said Brian Brown, president of the National Organization for Marriage, which on Thursday gave $250,000 to each of the four state campaigns opposed to same-sex marriage.

“The poll numbers that they’re interpreting as good for them are actually not good for them,” he said Friday, though noting that Washington could be tough for his side.

So far, the polls show support in the low-to-mid 50s for same-sex marriage:

-- In Maine, 53 percent said they will vote to back the initiative to institute gay marriage, compared to 44 percent who are opposed, according to Public Policy Polling (PPP), a firm that works for Democratic candidates and progressive causes. The mid-September poll was not paid for or authorized by any campaign or political organization. The margin of error was plus or minus 3.5 percent.

-- In Maryland, 54 percent said they’ll back the state law that was passed by the legislature earlier this year, compared to 40 percent who are opposed, according to Hart Research Associates, which conducted the July 24-28 poll for Marylanders for Marriage Equality. The margin of error was plus or minus 4.5 percent.

-- In Minnesota, the vote was a virtual tie, according to Public Policy Polling’s Sept. 10-11 poll, which had 48 percent supporting the amendment to ban gay marriage, 47 percent opposed and 5 percent undecided. The poll was not paid for or authorized by any campaign or political organization. The margin of error for the overall survey was plus or minus 3.4 percent.

-- In Washington, 56 percent of voters think the law legalizing same-sex marriage should be upheld, while 38 percent think it should be overturned, and 6 percent are not sure, according to a Sept. 7-9 SurveyUSA poll for KING-5 News in Seattle. The margin of error was plus or minor 4.3 percent.

Though the numbers appear to bode well for the same-sex marriage camp, they shouldn’t count on victory, Public Policy Polling said in its analysis of its Maine survey.

Did Supreme Court justice tip hand on gay marriage?

“Our experience in polling gay marriage is that if people say they’re undecided it usually means they’re opposed to it,” said Dean Debnam, the firm’s president. “Despite the 8 point lead for passage this should be seen as a very close race.”

Gregory B. Lewis, a professor at Georgia State University who has researched public opinion on gay rights for nearly two decades, believes the same-sex marriage side could prevail in Maine and Washington, with Maryland and Minnesota too close to call.

“Since 2004, we’re seeing a strong upward trend, about 2 percentage points a year -- more people are saying that they favor same-sex marriage than said so the year before” nationwide, said Lewis, who is chair of the Department of Public Management and Policy at Georgia State University.

Part of the uptick has been due to young people who support same-sex marriage hitting vote age, but primarily it has been a matter of voters changing their minds, he said.

Warbelow, of the HRC, said that even if people told pollsters one thing and voted another way, victory was within reach for her side.

“The polling is much higher than it’s ever been,” she said. “We were not seeing these kinds of numbers in prior years.”

“We’re hoping for all four, but even one will really change the conversation in the United States,” she added.

Six states have same-sex marriage, led by Massachusetts in 2004, and followed by Connecticut, New York, Iowa, New Hampshire, Vermont plus the District of Columbia. A total of 38 states have either a state law or constitutional amendment banning same-sex marriage.

RELATED:

Appeals court: Denying federal benefits to same-sex couples is unconstitutional

Despite marriage progress, gay couples face big hurdles to parenthood

Conservatives target Republicans who back gay marriage

Same-sex couple fights to stop deportation, gay marriage ban

Obama: 'I think same-sex couples should be able to get married'

Prop 8 backers ask Supreme Court to review gay marriage ban