Herring stressed the ban will be enforced in the meantime, meaning clerks will continue to deny marriage licenses to same-sex couples.
In a movement that began with Massachusetts in 2004, 17 states and the District of Columbia now allow gay marriage, most of them clustered in the Northeast. None of them is in the old Confederacy.
In just the past five weeks, federal judges struck down gay marriage bans in deeply conservative Utah and Oklahoma, but those rulings are on hold while they are appealed.
Gay rights advocates said Herring’s decision is an important gesture in the conservative South.
“It’s enormously powerful that Virginia is taking this position,” said James Esseks, director of the LGBT Project for the American Civil Liberties Union. “It is a solid part of the South. This is not the Northeast. This is not California.”
Richard Socarides, who was a senior policy adviser in the Clinton administration, called Herring’s action “a tipping point.”
“Virginia is now on the cutting edge of this,” he said. “I think it’s highly significant any time a state attorney general takes this position, but even more significant given the political makeup of the state is traditionally more conservative and now perhaps viewed as a swing state.”
Herring, whose Republican predecessor Ken Cuccinelli opposed gay marriage and abortion, was part of a Democratic sweep of the state’s top three offices in November. Virginia’s densely populated northern suburbs in the Washington, D.C., area are solidly Democratic, while other sections of the state remain solidly conservative Republican.
Gov. Terry McAuliffe, who led the Democratic slate of victories, said through a spokesman that he supports Herring.
The conservative Family Foundation of Virginia called Herring’s stand “disappointing and frightening,” while the Republican speaker of the Virginia House said Herring set a “dangerous precedent.”