A heart-shaped sign is posted Wednesday on a storefront in Montpelier, Vt. The state House on Tuesday narrowly achieved the votes necessary to override Gov. Jim Douglas’ veto of a bill allowing gays and lesbians to marry beginning Sept. 1.

Washington ? The next battleground over gay marriage could be the U.S. Capitol.

A preliminary vote by the District of Columbia city council to recognize same-sex marriages performed elsewhere puts the issue on a path to Congress, which has final say over D.C.’s laws. That may force lawmakers to take up the politically dicey debate after years of letting it play out in the states.

“Let’s be clear, this is a new era,” openly gay D.C. Council member David Catania said Wednesday, expressing optimism that the city’s law would clear Congress after a final council vote in May.

He said the measure is the first key step toward allowing gay marriages to be performed in Washington, too.

Unique D.C. situation

The council’s unanimous vote Tuesday came the same day Vermont became the fourth state to legalize gay marriage and the first to do so with a legislature’s vote. Court rulings led to same-sex marriages in three other states where it’s legal: Connecticut, Massachusetts and Iowa.

Like the measure approved in D.C., New York also recognizes same-sex marriages performed elsewhere but hasn’t issued its own marriage licenses for gay and lesbian couples.

The situation in D.C. is unique, though. After the legislation receives final approval from the council, supposed to come next month, the bill is subject to a 30-day congressional review. That review could be the new Congress’ first opportunity to signal its appetite for re-examining the Defense of Marriage Act, which bars federal recognition of same-sex marriages and allows states to do the same.

Since that federal law was passed in 1996, the debate has primarily played out in individual states. Vermont became the first state to legalize civil unions — in 1999 — and Massachusetts was the first state to legalize same-sex marriages, which began taking place there in 2004.

Advocates see Washington holding symbolic importance in the debate, but some stressed that there isn’t a dominant battleground in the quest for marriage equality.

“The district is equivalent to a small state, and the only difference is Congress’ ability to interfere with local decisions,” said David Smith, vice president of the Washington-based Human Rights Campaign.

‘National attention’

However, Jennifer Pizer, marriage project director at New York-based Lambda Legal, noted that D.C. is unique and influential because of its national focus.

“It’s the seat of the federal government,” she said.

Opponents said it remains to be seen whether a Democrat-controlled Congress will have any interest in repealing the city’s efforts. A spokesman for a House subcommittee that oversees the city’s affairs said Wednesday that the subcommittee was not commenting on the D.C. measure. Congress is in recess through April 17.

Peter Sprigg, vice president for policy at the Family Research Council, a Christian organization that opposes same-sex marriage, said the group was considering several strategies, including a legal challenge on whether the legislation violates the Defense of Marriage Act.

The Obama administration has spoken of working with Congress to repeal the Defense of Marriage Act, which was signed into law by President Bill Clinton. John Berry, who is gay and supports repealing the federal policy that defines marriage as between a man and a woman, was confirmed by the Senate last week to lead the Office of Personnel Management.

The issue of same-sex relationships in D.C. has previously run into trouble on Capitol Hill.

The district passed a law in 1992 recognizing domestic partnerships, which extended medical decision-making powers and other benefits to same-sex couples. But Congress restricted the city from spending its own funds to implement the law until 2002.