Republican lawmakers and some religious groups lambasted Herring, accusing him of not doing the job that he swore to do when he took his oath less than three weeks ago.

Herring argues that an attorney general has a duty to support laws that are constitutional but has “just as strong an obligation and duty” to not defend laws that he has concluded are unconstitutional after a careful and thorough review.

“I took an oath to uphold and support the Virginia Constitution and to support the United States Constitution,” Herring said. “A state law cannot violate the United States Constitution, and I swore to uphold both and the Supreme Court is clear that the U.S. Constitution is the supreme law of the land,” Herring said.

Last summer, the U.S. Supreme Court struck down parts of the Defense of Marriage Act, the law barring the federal government from recognizing same-sex marriages legalized by the states.

Bostic said last week that he and London are “grateful that the attorney general has come down on the side of fairness and equality, and we have confidence that the district court will do the same.”

Legal experts expect the hearing to last at least two hours — but say an immediate resolution is unlikely.