Alabama’s closely watched U.S. Senate race is a neck-and-neck contest as voter concerns about personal moral conduct weigh on the candidacy of Republican Roy Moore, according to a new Washington Post-Schar School poll.

With less than two weeks to go, support for Democrat Doug Jones among likely voters stands at 50 percent vs. Moore’s 47 percent — a margin of a scant three points that sets up a nail-biter for the oddly timed Dec. 12 special election.

The survey shows that allegations of improper sexual behavior against Moore, a former Alabama chief justice, hang heavily over a race that would favor a Republican under ordinary circumstances in this deeply conservative state.

Fifty-three percent of voters say Jones, a former federal prosecutor, has higher standards of personal moral conduct than Moore. In contrast, about a third of likely voters say Moore, who has cast his campaign as a “spiritual battle” with heavy religious overtones, has higher moral standards.

Among the 1 in 4 voters who say the candidates’ moral conduct will be the most important factor in how they vote, Jones leads, 67 percent to 30 percent. And Jones, whose strategy relies in part on peeling away Republican support from Moore, has the backing of 1 in 6 GOP-leaning likely voters. About 1 in 14 Democratic-leaning voters back Moore.

The race, in which the winner will fill the U.S. Senate seat vacated by Jeff Sessions when he became attorney general, has taken on national importance because of its implications for the Republican majority in the Senate. If Jones wins, the GOP will control the chamber by only 51 seats to 49.

Moore led Jones in most public polls before allegations became widely known last month, but support for Moore fell sharply afterward, with a mid-November Fox News poll showing him falling behind Jones by eight points. More recent automated surveys have found Moore regaining a slight edge.

The Post-Schar School poll was conducted Monday to Thursday by the research firm Abt Associates among a sample of 739 likely voters and carries a 4.5-point margin of sampling error. To avoid influencing the answers of respondents who have opinions about The Post’s coverage of allegations against Moore, interviewers disclosed The Post’s sponsorship of the survey only at the end of the interviews.

The survey shows that the Alabama electorate is divided on the validity of the allegations against Moore. While 35 percent of likely voters think Moore did make unwanted advances toward teenage girls, 37 percent say they are unsure or have no opinion. The smallest group — 28 percent of likely voters — says Moore did not make the advances that were alleged.

Women are more likely than men to find the allegations credible and to support Jones, with 41 percent of women saying Moore made unwanted advances compared with 28 percent of men saying the same. Moore leads by 15 points among men likely to vote, while Jones leads by 18 points among likely female voters.

There is also a stark partisan and ideological divide in how voters have processed the allegations, with many Republicans and GOP-leaning groups expressing skepticism.

Fewer than 1 in 6 Republican-leaning likely voters say they believe that Moore made unwanted advances toward female teenagers. That view is held among similarly small shares of white evangelical Protestants and those who say they approve of President Trump, who in recent days has questioned the allegations and urged Alabamians to prevent Jones from winning the seat.

More than three-quarters of each of those groups support Moore over Jones.

At the same time, Jones is running well ahead of his own party’s dismal track record in a state that last elected a Democratic U.S. senator in 1992, when Sen. Richard C. Shelby won. He defected to the Republican Party two years later.

In the Post-Schar School poll, Jones has the backing of 33 percent of white voters in the state. Barack Obama won just 15 percent of white votes in Alabama in his 2012 presidential reelection, according to exit polls.

“On the allegations, they have made an impact. There is no doubt,” said Mark J. Rozell, the dean of the Schar School of Policy and Government at George Mason University. “Anybody with an R next to their name should be comfortably ahead in this state.”

A sizable share of Alabama’s Republican-leaning voters are clearly torn over the choice before them as they weigh their concerns about Moore against their desire to see Alabama send another Republican to the Senate.

Fewer than half, 44 percent, of likely voters say they would prefer to see a Democrat representing Alabama in the Senate, while 50 percent of likely voters say they favor electing a Republican.

Others say that they are unlikely to vote because they dislike both candidates. “I’m fed up. A lot of people are down here,” said Terry Anderson, 54, of Hartford, Ala. Anderson is an independent who participated in the poll and said he was not going to vote. “I think I’ll just let it all fall out on its own.”

Republican-leaning likely voters are particularly unhappy with the role that national Republican leaders calling for Moore to drop out have played in the race. Nearly 3 in 4 say that outsiders should stay out of Alabama politics, while one-fourth say the national Republican leaders are justified in voicing their opinions.

Senate Majority Leader Mitch McConnell (Ky.) and other senior GOP senators have called on Moore to exit the race, and conservative stalwarts such as Sens. Mike Lee (R-Utah) and Ted Cruz (R-Tex.) have withdrawn their endorsements of Moore. The Republican National Committee and the National Republican Senatorial Committee have cut ties with the Moore campaign.

In Alabama, the Republican Party has closed ranks around Moore, arguing either that the allegations against him are questionable or that putting a Republican in the U.S. Senate is a more important consideration. Shelby, Alabama’s senior senator, is the only statewide elected official to announce that he did not vote for Moore but opted to write in a different person’s name.

Republicans have a clear advantage in party identification in Alabama, and Trump defeated Hillary Clinton by 28 points in the state last November. But Democrats say they are more enthusiastic about turning out for the special election. By 47 percent to 38 percent, more Democratic-leaning voters than Republican-leaning voters say it is “extremely important” to vote in the election. Democratic-leaners are also 12 points more likely to say they are following the race “very closely” and 10 points more likely to say they are “absolutely certain to vote.”

Jones’s campaign is banking on strong support and turnout among African American voters, who make up one-quarter of likely voters in the Post-Schar School poll. African American likely voters support the Democrat 93 percent to 6 percent.

Countering Democrats’ enthusiasm, Moore’s supporters have voted more in recent low-turnout elections, including the U.S. Senate primary in which Moore prevailed.

Several women have accused Moore, 70, of initiating unwanted sexual encounters with them, mostly when they were teenagers and he was in his 30s. Leigh Corfman told The Post that she was 14 at the time of the alleged encounter. Moore has denied the allegations of sexual misconduct, arguing that he is the victim of a political conspiracy by Republicans, Democrats, the news media, socialists and lesbian, gay, bisexual and transgender people “who want to change our culture.”

At the same time, Moore has not ruled out that he dated teenagers with their parents’ permission when he was in his 30s. “If I did, I’m not going to dispute these things, but I don’t remember anything like that,” Moore said on Sean Hannity’s radio show on Nov. 10 in response to claims that he had dated 17- or 18-year-old girls.

Other women interviewed by The Post in recent weeks said that Moore pursued them when they were between the ages of 16 and 18 and he was in his early 30s. The Post has spoken to a dozen people who worked at the Gadsden Mall in Gadsden, Ala., in the late 1970s and early 1980s and said they recalled Moore as a frequent presence. Several women who worked there said they remember Moore making them feel uncomfortable.

The Alabama electorate is nearly unanimous in its view that men in their 30s should not date 16-year-old girls. Among likely voters, 91 percent say such relationships are never appropriate. Fifty-six percent say older men dating teenagers was not more acceptable in the 1970s, although 32 percent think it had been more acceptable, including 41 percent of Moore’s supporters.

Of the social issues that have dominated much of the debate in the race, abortion has been a bigger asset for Moore than his campaign focus of fighting against those who would increase protections for gay, lesbian and transgender people.

Just over 3 in 10 Republicans and Republican-leaning independents say they trust Jones more to handle rights for gay and transgender people, while 51 percent say they have greater trust in Moore. By contrast, 80 percent of the same group expresses greater trust for Moore on abortion, and 78 percent trusts him more on health care.

Moore has argued that judges who support same-sex marriage or legalized sodomy should be impeached, as both positions go against his view of divine law, which he says has supreme authority over the Constitution.

Republican-leaning voters with college degrees are among the most likely to trust Jones on gay and transgender rights — 44 percent trust him, while 39 percent trust Moore. Among Republicans with some college education or less, Moore leads, 57 percent to 25 percent, on trust to handle these issues.

The poll was conducted by The Post and the Schar School of Policy and Government at George Mason University via landline and cellphone.

Emily Guskin contributed to this report.