The effort to repeal a federal ban on gay marriage gained some momentum on Tuesday as President Obama and 27 senators endorsed a measure to end the Defense of Marriage Act.

Sen. Diane Feinstein (D-CA) announced a bill that would strike down the Defense of Marriage Act, which she called unconstitutional and wrong. If passed, the legislation would allow same-sex couples access to more than 1,000 benefits and protections they are currently denied because the government does not recognize their marriages as valid.

The bill has gained 27 Democratic co-sponsors, as well as the backing of the Obama administration. Obama instructed the Justice Department to stop defending the act in court but has studiously avoided applying pressure or publicly supporting same-sex marriage, saying the issue was up to Congress and the states to decide.

Feinstein introduced the bill as Congress prepared to convene a hearing in which same-sex couples are set to testify about how the Defense of Marriage Act effects their lives. Feinstein acknowledged the bill's dim prospects, saying she anticipated a long march and  that it's a hard time because of the tea party and the ideological bent, but said public sentiment is shifting.

I think eyes have opened, Feinstein said. More and more people across this land know people who are gay, who want to have a lasting relationship, who look at marriage as an economic agreement as well as an emotional agreement.

While New York's recent legalization for same-sex marriage was a source of jubilation for gay couples and gay rights activists, the enthusiasm was tempered by the fact that the Defense of Marriage Act still barred married same-sex couples from access to a wide range of benefits, including shared Medicaid and Social Security. Same-sex couples must contend with a patchwork of statutes as they travel between different states, and immigration law grants permanent residence status to an immigrant who marries a citizen -- but not if they are the same sex.

Still advocates said at the time that New York could provide an impetus for action on the federal level.

New York's marriage law will reverberate around the country in a different way politically, said Suzanne Goldberg, Director of Columbia Law School's Center for Gender and Sexuality. There's a certain moral and political force that comes with New York granting marriage equality after such a tough fight here, simply because New York is such a large and influential state.