Brian Brown, president of the National Organization for Marriage (NOM), vowed to continue fighting against marriage equality even if the Supreme Court legalizes it nationwide.

NOM, the nation's most vociferous opponent of allowing gay couples to marry, is preparing for its second annual March for Marriage, a rally and march to the steps of the U.S. Supreme Court.

Speakers at Thursday's event include former presidential candidates Rick Santorum and Mike Huckabee and San Francisco Archbishop Salvatore Cordileone.

(Related: Nancy Pelosi calls NOM's anti-gay marriage march “venom masquerading as virtue.”)

Speaking to the AP, Brown said he believes the issue will be settled at the Supreme Court and that a ruling upholding state bans might encourage a movement in some marriage equality states to reverse course.

“We'd put this back in the hands of the democratic process,” said Brown. “We would have the people deciding for themselves.”

“We won't go away,” Brown said of a possible court ruling legalizing same-sex marriage nationwide.

“In the next year or so, we'll either have a massive victory at the Supreme Court, or we'll need to fight for 10, 20 years to undo the damage that the court has done,” he said.