In last year’s presidential election, Barack Obama won 70 percent of the gay vote, John McCain just 27 percent.

Does that kind of clearly dominant constituency — one that’s more politically-attuned than the rest of the electorate — come with any political obligation regarding gay rights? You bet it does, and this weekend Obama is acknowledging the debt.

On the eve of Sunday’s National Equality March, expected to draw thousands to Washington, he’s addressing the Human Rights Campaign, a national gay rights group.

So far, his is a mixed record.

While Obama remains opposed to marriage among same-sex couples, in June he extended some benefits to the same-sex partners of federal employees. And he has taken steps to include among his administration openly gay officials.

John Berry, the director of the Office of Personnel Management, is the government’s highest-ranking gay official. David Huebner, chief lawyer for the Gay & Lesbian Alliance Against Defamation, has been nominated ambassador to New Zealand and Samoa. Mr. Huebner would be just the second openly gay US ambassador. (The first was appointed by Bill Clinton.)

Marriage and the US military’s “don’t ask, don’t tell” policy on gay men and women in uniform remain the toughest issues for the nation — and especially for Obama.

The Pew Research Center reported Friday that while most Americans favor civil unions for same-sex couples, they remain opposed to gay marriage.

It’s an issue that transcends government policy to an unusual extent, carrying significant moral and religious overtones. Pew finds that “nearly half of the public (49 percent) says homosexual behavior is morally wrong, while 9 percent say it is morally acceptable and 35 percent say it is not a moral issue.”

Meanwhile, the armed services for years have wrestled with the Pentagon’s policy regarding gay service members — a policy which senior retired officers (and even some on active duty) increasingly have spoken out against at a time when the troops, like the relatively young cohort of Americans they’re part of, don’t see the point in discriminating against gay men and lesbians.

Many gay rights advocates are losing patience with Obama who (unlike Bill Clinton) has no inclination to jump right into the military issue.

“Eleven months after his election, he has failed to deliver on any of his commitments to gay Americans, but even worse has been his refusal to engage around these issues,” Richard Socarides, who advised President Bill Clinton’s administration on gay and lesbian policy, told the Associated Press.

“What he needs to do now is engage and deliver,” said Socarides. “Spend some of his political capital on ending the gay military ban, a hugely symbolic issue. And with no intellectually sound arguments left against it, come out squarely for gay marriage equality.”

Obama also is being nudged to retire today’s military policy by many members of Congress. Led by Rep. Patrick Murphy (D) of Pennsylvania (the first Iraq war veteran elected to Congress) 176 House members have signed on to a bill doing away with don’t ask, don’t tell.

Meanwhile, the US Senate — and just last week, the US House of Representatives — have passed versions of a bill broadening the federal hate-crime law to cover violence against gays.

Obama is eager to sign the new hate crimes law. And White House officials push back against the notion that the president is dragging his feet on gay rights.

“The president has been very clear. He’s not hiding, he’s not avoiding [the gay and lesbian] issue,” Melody Barnes, the president’s top domestic policy adviser, told the Washington Post. “He has walked into a range of different communities as well as looked into the eyes of those in the GLBT community and been very clear about what he supports and what he wants done and the way he thinks it’s practical to get it done.”