Utah Representative Jason Chaffetz has vowed to lead an effort in Congress to block a gay marriage bill approved in the District of Columbia Tuesday.

With an 11 to 2 vote, lawmakers approved the gay marriage bill, which is expected to be signed by Mayor Adrian Fenty before Christmas. Under Home Rule, Congress has final say on laws approved in the District.

Chaffetz, a freshman representative, told the Salt Lake Tribune that he'll introduce a resolution in January.

“It's going to be exceptionally difficult because Democrats have us outnumbered by large amounts,” he said. “Nevertheless, we're going to try.”

To block the gay marriage bill, a resolution needs the approval of both houses of Congress and the president's signature within 30 legislative days. A formidable feat considering Democrats control both the House and Senate.

“If it were put up for a vote, traditional marriage would win. It would win with a congressional vote, and it would win with the residents of Washington, D.C.,” Chaffetz said referring to attempts by opponents to put a gay marriage question on the ballot.