Maryland voters are leaning toward legalizing same-sex marriage next month, something that has never happened at the ballot box anywhere in the nation, a new Washington Post poll finds.

A ballot question on whether to uphold a state law allowing gay nuptials is favored 52 percent to 43 percent among likely voters, according to the poll, reflecting a long-term trend toward greater acceptance of gay unions that has included President Barack Obama's backing this year.

Same-sex marriage has become legal in six states and Washington through legislative or court action. But it has never been authorized by a popular vote.

Voters in Maine and Washington state will also be presented with the issue Nov. 6 — the first time since 2009 that any state has been asked whether to legalize same-sex marriage.

Although the measures are leading in polls in all three states, the election results are hardly a given. Historically, opposition to same-sex marriage at the ballot box has been stronger than polls suggested, and an expected ad blitz from opponents in Maryland has barely begun.

On Question 6 in Maryland, voters will decide whether to uphold a law championed by Gov. Martin O'Malley (D) that won narrow legislative approval this year and was swiftly petitioned to referendum by opponents.

The Post poll finds sharp differences in support for Question 6 by race, region, age and political party.

Both sides in Maryland have been heavily targeting African American voters in a state where blacks make up a larger percentage of the electorate than anywhere outside the Deep South.

Proponents have featured ministers and civil rights leaders in their ads. Opponents have networked for months through black churches.

In The Post poll, white voters break in favor of gay nuptials, 56 percent to 39 percent.

But African Americans — who had become more supportive in national polls this year — tilt against the measure. In the new survey, 42 percent of black voters support the measure, and 53 percent oppose it.

Among Democrats, the racial divide is even more stark. While 76 percent of white Democrats back Question 6, support is 40 percent among black Democrats. Republicans in the state oppose the measure by 2 to 1, while independents support it 2 to 1.

Leprenia Lindsay, 43, is among those in favor of the measure.

"I think given the day and time we live in, and the progression of how society has changed, I would support same-sex marriage," said Lindsay, an African American who lives in Temple Hills, Md. "If someone is your life partner, that person should be able to assist in making life-and-death decisions; it shouldn't be up to some family member you haven't seen in 20 years."

Lindsay said her views began to evolve on the topic in the late 1990s when she returned to the Washington area shortly after college and took an entry-level job at Banana Republic. At an employee orientation she began reading about domestic partnership benefits.

"I thought, 'Oh my God, times are changing,' " she recalled Wednesday.

Lindsay said that even as she has come to accept gay marriage, her 15-year-old son has developed an opposition to it. "He is very accepting of people with alternative lifestyles, but doesn't believe they should be able to get married," she said.

That's a view common to a generation of older churchgoers in Maryland, the poll found.

"The Bible says there's only one marriage, the covenant between a man and a woman," said Melissa Smith, a retired elementary school principal who lives in Laurel. "They should have their beneficiaries; their families shouldn't be able to ban them from each other's deathbeds, but I don't think they need to be married in order to have that."

Smith, 61, said her views are driven by her faith and remain unchanged even though her late twin brother was openly gay. "He has nothing to do with my views," she said. "This is about what the Bible says."

Religion plays a big role in voters' views on the matter, The Post poll found. Among opponents of same-sex marriage, two-thirds say their religious beliefs and opinions are the chief influence on their views.

Supporters cite more varied motivations, including personal and educational experiences, and family and friends. Just 9 percent say religion is the biggest influence on their views.

Age also plays a big factor in Marylanders' views of same-sex marriage. Sixty-four percent of those 18 to 39 support Question 6. That drops to 51 percent of those ages 40 to 64, and 40 percent of those 65 and older.

The telephone poll was conducted Oct. 11-15 among a random sample of 1,106 Maryland adults. Interviews were conducted on conventional land-line and cellular telephones, and in English and Spanish.

The sample of 934 registered voters and 843 likely voters each have a margin of sampling error of plus or minus four percentage points.

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Washington Post staff writers Rachel Karas, Jon Cohen and Scott Clement contributed to this report.