Conservatives have bitterly accused them of shirking their sworn responsibility. But the A.G.s say that the legal case against gay marriage is crumbling and that it would be improper for them to argue positions they have concluded are clearly unconstitutional.
Attorneys general in five states Virginia, Pennsylvania, California, Illinois and, this week, Nevada have declined to defend same-sex marriage bans against lawsuits filed by gay couples, while a sixth, in New Mexico, challenged longstanding legal interpretations that said such unions were impermissible there. The A.G.s are all Democrats.
Also this week: The Democrat running for Colorado attorney general called on the current Republican officeholder to stop defending the state's prohibition. And in Texas, Democratic gubernatorial candidate Wendy Davis demanded that her likely GOP opponent, Attorney General Greg Abbott, do the same.
The developments illustrate the growing public acceptance of gay marriage and the rapidly shifting legal landscape since last summer, when the U.S. Supreme Court struck down a key part of the Defense of Marriage Act that denied gay married couples the federal benefits and privileges enjoyed by heterosexual couples.
It's unusual, but not unheard of, for attorneys general to decline to defend a state law.
Gay-marriage opponents argue that attorneys general, as the top lawyers for their states, are supposed to represent their client the state regardless of personal beliefs.
"It shows a complete collapse of the line between law and politics," said Ed Whelan, president of the Ethics and Public Policy in Washington. "The defense of these laws is not being litigated the way it ought to be, and defenders of marriage laws will have ample reason to believe the process is rigged against them."
But Brian Moulton of the Human Rights Campaign said the moves demonstrate the impossibility of defending gay-marriage bans in court. He noted that in three deeply conservative states where the gay-marriage movement recently won legal victories, the attorneys general were on the losing side.
"When you have federal district judges in places as diverse as Utah, Oklahoma and now Kentucky coming to the same conclusion, that points to an emerging legal consensus," Moulton said. "I don't think it's shocking that you have attorneys general who are looking at how the law is emerging and are coming to similar conclusions."
The first attorney general to stop defending his state's ban was California's Jerry Brown, now governor. The U.S. Supreme Court soon ruled that gay-marriage foes did not have the legal standing to argue the case in the A.G.'s absence. With no opposing argument, the ban fell last year.
Illinois' Lisa Madigan took a similar stand in 2012, but before the case could go to trial, the Legislature legalized same-sex marriage. Pennsylvania's Kathleen Kane bowed out last year, but the Republican governor's office assumed the duty.
In Virginia, the judge who struck down the ban as unconstitutional put the ruling on hold while it is appealed. If it is ultimately allowed to take effect, Virginia could become the first state in the South to allow gay couples to wed.
The newly elected Herring was in office less than two weeks when he announced last month that he would ask the court to overturn the state's 2003 voter-approved ban. Herring had supported it a decade ago but said he had since concluded it was unconstitutional.
Republicans were furious.
"I'm a lawyer," said state Delegate Todd Gilbert. "I take positions I may find personally distasteful when they may benefit a client because that's my role as an attorney."
North Carolina Attorney General Roy Cooper, a Democrat, has taken a similar stand. While he supports same-sex unions, he said in a statement: "When legal arguments exist to defend a law, it is the duty of the Office of the Attorney General under North Carolina law to make those arguments in court regardless of whether I agree with the law."
Nevada Attorney General Catherine Cortez Masto said in an interview this week that a recent federal appeals court ruling that gays could not be excluded from juries because of their sexual orientation had "gutted" the argument the state was using to ban gay marriage.
"You have to look at the law, look at the legal merits and see if you have a good-faith defense," she said, adding that her personal views on gay marriage are irrelevant.
Observers say the next attorney general in the hot spot may be Oregon's Ellen Rosenblum. Last year, the Democrat signed on to Supreme Court briefs arguing it was unconstitutional to deny gays the right to marry. A federal lawsuit challenging Oregon's ban is moving ahead. A Rosenblum spokesman had no comment Friday.