Wolf told Attorney General Eric Holder at an appropriations subcommittee hearing that the Obama administration had abandoned its duty.
"It almost looks like a political decision," Wolf said. "I think it's inappropriate and it's a bad decision."
But Holder said that the legal landscape has changed "fairly fundamentally" since DOMA was passed, pointing to the Supreme Court's striking down of laws regulating private homosexual conduct and Congress' repeal of the military's "Don't Ask, Don't Tell" policy.
"Given the history of discrimination that gays and lesbians have endured in our nation's history and other factors, and other reasons that a heightened scrutiny was potent," Holder said. "It was not a decision I took lightly."
He also said that while it was unusual for the Department to take such an action, it wasn't unprecedented -- pointing out that now-Chief Justice John Roberts himself declined to defend a law passed by Congress when he was in the Justice Department in the early 1990s.