In another milestone moment in the pursuit of equal rights for LGBT Americans, the U.S. Senate voted by a narrow margin on Monday to bring to the floor the Employment Non-Discrimination Act.

By a vote of 61-30, senators invoked cloture on the legislation as Sen. Mazie Hirono (D-Hawaii) presided. The vote enables up to 30 hours of debate and amendments before a vote for final passage, which is expected Wednesday.

The 54 Democrats who voted for ENDA, whose chief sponsor is Sen. Jeff Merkley (D-Ore.), consisted of the Democrats who co-sponsored ENDA as well as Sens. Cory Booker (D-N.J.), Joe Manchin (D-W.Va.) and Mark Pryor (D-Ark.). Sen. Claire McCaskill (D-Mo.), an ENDA co-sponsor, didn’t vote.

On the Republican side, additional votes came from Sens. Kelly Ayotte (R-N.H.), Rob Portman (R-Ohio) and Pat Toomey (R-Pa.). Other votes came from Sens. Orrin Hatch (R-Utah), who voted for the bill in committee, and Sen. Dean Heller (R-Nev.), who articulated his support earlier in the day. Sen. Lisa Murkowski (R-Alaska), who also voted for ENDA in committee, didn’t vote.

Including the Republican original co-sponsors of ENDA — Sens. Susan Collins (R-Maine) and Mark Kirk (R-Ill.) — the bill had seven Republican votes. As he indicated he would, Sen. Jeff Flake (R-Ariz.) voted “no” after entering the Senate chamber following Sen. Tammy Baldwin (D-Wis.), apparently after a conversation with her.

As the vote took place, there were concerns there would be insufficient votes to invoke cloture on ENDA because of Murkowski’s absence, but Portman and Toomey, after intense conversations with colleagues, entered the Senate chamber just before the vote was called to vote “yes.”

The roll call of the vote for cloture on ENDA can be found here.

Prior to the vote, lawmakers who support the legislation spoke out in favor of the bill, touting it as a means of advancing equal opportunity and the “American Dream.”

Senate Majority Leader Harry Reid (D-Nev.) said ENDA is necessary because discriminating against gay workers is legal in 29 states and for being transgender in 33 states.

“The patchwork of state laws excludes tens of millions of Americans from basic protection against discrimination,” Reid said. “It is simply not good enough. It is [time to] pass a federal law that ensures all Americans regardless of where they live can go to work unafraid to be who they are. As long as hardworking, qualified Americans can be denied job opportunities, fired, or harassed because of their sexual orientation or gender identity, all workers are at risk.”

Sen. Tom Harkin (D-Iowa), chair of the Senate Health, Education, Labor & Pensions Committee from which the legislation originated, said passage of ENDA would say LGBT Americans “deserve the same civil rights protections as all other Americans.”

“We are here because, even though most Americans believe firing or refusing to hire someone based their sexual orientation is illegal, they are incorrect,” Harkin said. “The majority of Americans, more than 56 percent, live in states where it is perfectly legal to fire someone or to refuse to hire them because of who they are, a lesbian, gay, bisexual or transgender citizen.”

Amid concerns that the religious exemption is too broad and calls from some LGBT advocates for lawmakers to speak out against it, Harkin said the language is necessary to ensure bipartisan support.

“This is a compromise that has been hard for strong advocates of civil rights and civil liberties, including me, to accept,” Harkin said. “But it is an exemption that has helped to persuade some members of strong faith that ENDA should become law. I would point to my friend Sen. Hatch, who supported this bill in committee, as just one important example of senators who are satisfied that this exemption serves to reconcile the strictures of their faith with fundamental fairness in the workplace.”

Sen. Tammy Baldwin (D-Wis.), the only openly gay member of the Senate, said she understands some lawmakers may have political difficulties in supporting the legislation, but encouraged her colleagues to stand on the right side of history.

“I realize that for some, this is not an easy vote,” Baldwin said. “I understand that for some they may believe that it’s not good politics. But I want to say that I have a deep respect for those who choose to stand on the side of progress for our country this week. So for those that stand up this week and answer the call for courage, I can say with confidence your courage will be respected and remembered when this struggle is written.”

Sen. Mark Kirk (R-Ill.), a Republican and original co-sponsor of ENDA, spoke on the Senate floor for the first time in two years after suffering a stroke.

“I have been silent for the last two years due to a stroke a little under two years ago,” Kirk said. “I have risen to speak because I’m so passionate in enacting the ENDA statute.”

It’s the first time a version of ENDA with transgender protections has come to the floor of either chamber of Congress. In 2007, controversy ensued after gay former Rep. Barney Frank dropped the transgender provision from the bill over the concern an inclusive bill couldn’t be passed.

Mara Keisling, executive director of the National Center for Transgender Equality, said the cloture vote on ENDA is “an important step” toward ensuring workplace fairness for everyone, including transgender workers.

“Tonight’s procedural vote is an important step toward making sure our country gives every worker, including transgender workers, the same chance at having security at work and caring for the ones they love,” Keisling said. “The Employment Non-Discrimination Act does just that.”

It’s also the first time the Senate has considered ENDA since 1996, when the bill came to the floor as part of a deal to consider the Defense of Marriage Act and failed by one vote.

The cloture vote is also significant because the 60-vote threshold necessary to overcome a filibuster is higher than the simple majority needed for final passage. It means the legislation is almost certain win final approval in the Senate.

Amendments are expected in the coming days. After his “yes” vote on cloture, Portman announced he’ll introduce an amendment that would prevent retaliation against religious organizations and make changes to the introductory section that highlight and explain the importance of religious liberty.

White House Press Secretary Jay Carney praised lawmakers for voting for cloture on the legislation, saying President Obama welcomes the bipartisan support for the bill.

“He thanks the lawmakers from both sides of the aisle who have stood up for America’s core values of fairness and equality, and looks forward to the Senate’s consideration of ENDA,” Carney said. “He also encourages lawmakers to ensure that the legislation remains true to its goals as it is considered.”

LGBT advocates praised the vote on ENDA as a milestone moment in anticipation of additional debate that will take place in the days to come.

Chad Griffin, president of the Human Rights Campaign, said the cloture vote indicates the time has come for ENDA’s passage.

“Today we saw American democracy in action with the U.S. Senate finally following the will of a diverse and bipartisan collection of Americans calling for workplace fairness,” Griffin said. “With a super majority of Senators, more than 100 major American companies, and more than two-thirds of Americans all standing proudly in support of ENDA, there is tremendous momentum behind this common-sense bill. ENDA’s time has come, and we’re not going to stop fighting until it is passed once and for all.”

Tico Almeida, president of Freedom to Work, drew attention to the bipartisan support the legislation won on the Senate floor.

“The U.S. Senate has taken a historic step toward ensuring that gay and transgender Americans have the same workplace protections that give all Americans a fair shot to succeed on the job,” Almeida said. “Today’s strong bi-partisan vote total for the Employment Non-Discrimination Act reflects that majorities of Americans from both parties believe nobody should get fired or harassed just because of who they are or whom they love.”