Archbishop Timothy Dolan, president of the U.S. Conference of Catholic Bishops, wants President Barack Obama to push the reset button on gay marriage.

Dolan, who as the archbishop of New York actively lobbied lawmakers against legalizing gay marriage, on Tuesday called on the president to enforce and defend in court the Defense of Marriage Act (DOMA), the 1996 law that bans federal agencies from recognizing the legal marriages of gay and lesbian couples.

Currently such unions are legal in six states, New York being the latest, and the District of Columbia.

Earlier this year, Obama instructed the Department of Justice to no longer defend DOMA in court. House Republicans have taken on that responsibility. Since then, the president has announced support for a bill that would repeal DOMA.

Dolan expressed “grave concerns” about the moves which “escalate the threat to marriage and imperil the religious freedom of those who promote the defense of marriage.”

“Mr. President, I respectfully urge you to push the reset button on your Administration's approach to DOMA,” Dolan wrote. (Read the full letter.)

After New York legalized gay marriage in June, Dolan apologized for calling such unions an “ominous threat” to society and “a violation of what we consider the natural law that's embedded in every man and woman.”

“To the gay community, I love you very much. If anything I ever said or did would lead you to believe that I have anything less than love and respect for you, I apologize,” Dolan said.