WASHINGTON (AP) — Same-sex couples would be allowed to marry in the nation’s capital under a bill introduced Tuesday by a District of Columbia councilman.

The bill was almost certain to pass and had been expected for some time. But whether it becomes law is more complicated because Congress gets to review D.C. legislation before it takes effect.

At least one Republican congressman has said he will work to have the bill defeated if it passes the D.C. council.

“Some fights are worth fighting for,” said U.S. Rep. Jason Chaffetz of Utah, who thinks Democrats in Congress would likely block any vote on D.C.’s measure. “This is one of them.”

The city began in July recognizing same-sex marriages performed elsewhere.

Congress had a chance to act on that legislation, but it quietly passed earlier this year.D.C. Councilman David Catania introduced the new bill at a standing-room only council meeting. The independent and one of two openly gay council members said he hopes for a vote in December.

“There is no question that we are about to embark on an exciting journey here in the district,” he said.

His bill specifically said religious leaders and institutions are not required to perform the marriages or rent their space for same-sex ceremonies.

If the bill becomes law, the city will follow Massachusetts, Connecticut, Iowa and Vermont, which issue marriage licenses to same-sex couples. New Hampshire will begin issuing them in January.

The legislature in Maine has also passed a same-sex marriage bill, but voters will decide in November whether to reverse it. California briefly issued licenses before voters passed a law stopping the practice.

In the District of Columbia, the bill was co-introduced by 10 of the city council’s 13 members and has the support of the mayor.

If Congress blocked the bill, it would be rare. In the past 25 years, Congress has only rejected three pieces of legislation.

According to Brian Flowers, the city’s general counsel, the last time was in 1991, when Congress rejected a law that would have permitted taller buildings in the city.

In 1999, Congress amended a bill so that city medical marijuana would not be legalized. Congress also repealed a law that would have required D.C. government employees to be city residents.

Same-sex marriage supporters cheered the bill’s introduction. D.C. residents Juan Rondon and Edward Grandis came to the meeting wearing T-shirts that displayed copies of their California marriage license.

“I feel a sensation of relief,” Grandis said.

According the U.S. Census Bureau, there were about 3,500 same-sex couples living together in the city in 2008, though the number has a wide margin of error. D.C. has 600,000 residents.

Rick Rosendall, vice president for political affairs for the Gay and Lesbian Activists Alliance, said he was proud of the city but acknowledged: “We have a long way to go, of course.”

The Catholic Church and Washington’s archbishop, Donald Wuerl, have been vocal in opposing the legislation.

And a group led by Bishop Harry Jackson, the pastor of a Maryland church, had previously asked D.C.’s board of elections to authorize a ballot initiative defining marriage as between a man and a woman.

The board will consider the request later this month.

“We are prepared to go to court,” Jackson said.

• Jessica Gresko