WASHINGTON >> The Senate approved legislation outlawing workplace discrimination against gay, bisexual and transgender Americans, demonstrating the nation’s quickly evolving attitude toward gay rights nearly two decades after Congress rejected same-sex marriage.

Fifty-four members of the Democratic majority and 10 Republicans voted Thursday for the first major gay rights bill since Congress repealed the ban on gays in the military three years ago. The vote in favor of the Employment Non-Discrimination Act was 64-32.

Hawaii Democratic senators Brian Schatz and Mazie Hirono voted in favor of the bill.

Two opponents of a similar measure 17 years ago, Arizona Republican Sen. John McCain, the presidential nominee in 2008, and Republican Sen. Orrin Hatch of Utah, backed the measure this time.

“We are about to make history in this chamber,” Sen. Susan Collins, R-Maine and a chief sponsor of the bill, said shortly before the vote.

The enthusiasm of the bill’s supporters was tempered by the reality that the Republican-led House, where conservatives have a firm grip on the agenda, is unlikely to even vote on the legislation. Speaker John Boehner, R-Ohio, maintains his longstanding opposition to the measure, arguing that it is unnecessary and certain to create costly, frivolous lawsuits for businesses.

Outside conservative groups have cast the bill as anti-family.

President Barack Obama welcomed the vote and urged the House to act.

“One party in one house of Congress should not stand in the way of millions of Americans who want to go to work each day and simply be judged by the job they do,” Obama said in a statement. “Now is the time to end this kind of discrimination in the workplace, not enable it.”

Gay rights advocates hailed Senate passage as a major victory in a momentous year for the issue. The Supreme Court in June granted federal benefits to legally married same-sex couples, though it avoided a sweeping ruling that would have paved the way for same-sex unions nationwide. Illinois is on the verge of becoming the 15th state to legalize gay marriage along with the District of Columbia.

Supporters called the bill the final step in a long congressional tradition of trying to stop discrimination, coming nearly 50 years after enactment of the Civil Rights Act and 23 years after the Americans with Disabilities Act.

“Now we’ve finished the trilogy,” Sen. Tom Harkin, D-Iowa, a chief sponsor of the disabilities law, said at a Capitol Hill news conference.

The first openly gay senator, Democrat Tammy Baldwin of Wisconsin, called the vote a “tremendous milestone” that she will always remember throughout her time in the Senate.

Democrats echoed Obama in pushing for the House to act, with Sen. Dick Durbin of Illinois reminding the GOP leader of the history of his party.

“The Republican Party in the United States of America came into being in the 1980s over the issue of slavery, and the man who embodied the ideals of that Republican Party was none other than Abraham Lincoln, who gave his life for his country to end discrimination,” Durbin said. “Keep that proud Republican tradition alive.”

In the Senate, opponents of the legislation remained mute through three days of debate, with no lawmaker speaking out. That changed on Thursday, as Republican Sen. Dan Coats of Indiana said the legislation would force employers to violate their religious beliefs, a direct counter to rights embodied in the Constitution.

“There’s two types of discrimination here we’re dealing with, and one of those goes to the very fundamental right granted to every American through our Constitution, a cherished value of freedom of expression and religion,” Coats said.

The Senate rejected an amendment sponsored by Republican Sen. Pat Toomey of Pennsylvania that would have expanded the number of groups that are covered under the religious exemption. Opponents argued that it would undermine the core bill.

If the House fails to act on the bill, gay rights advocates are likely to press Obama to act unilaterally and issue an executive order barring anti-gay workplace discrimination by federal contractors.

Backers of the bill repeatedly described it as an issue of fairness.

“It is well past time that we, as elected representatives, ensure that our laws protect against discrimination in the workplace for all individuals, that we ensure … some protections for those within the LGBT community,” said Sen. Lisa Murkowski, R-Alaska, who described the diversity in her state.

Murkowski’s support underscored the generational shift. Seventeen years ago, when a bill dealing with discrimination based on sexual orientation failed by one vote in the Senate, the senator’s father, Frank, voted against it. That was the same year that Congress passed and President Bill Clinton signed the Defense of Marriage Act.

Current federal law prohibits discrimination on the basis of sex, race and national origin. But it doesn’t stop an employer from firing or refusing to hire workers because they are gay, lesbian, bisexual or transgender.

The bill would bar employers with 15 or more workers from using a person’s sexual orientation or gender identity as the basis for making employment decisions, including hiring, firing, compensation or promotion. It would exempt religious institutions and the military.

By voice vote Wednesday, the Senate approved an amendment from Republican Sens. Rob Portman of Ohio and Kelly Ayotte of New Hampshire that would prevent federal, state and local governments from retaliating against religious groups that are exempt from the law.

Likely Senate approval of the overall bill reflects the nation’s growing tolerance of gays and the GOP’s political calculation as it looks for support beyond its core base of older voters. A Pew Research survey in June found that more Americans said homosexuality should be accepted rather than discouraged by society by a margin of 60 percent to 31 percent. Opinions were more evenly divided 10 years ago.

Twenty-two states and the District of Columbia have approved laws banning workplace discrimination on the basis of sexual orientation, and 17 of those also prohibit employers from discriminating based on gender identity.

About 88 percent of Fortune 500 companies have adopted nondiscrimination policies that include sexual orientation, according to the Human Rights Campaign. About 57 percent of those companies include gender identity.

Sens. Bob Casey, D-Pa., Tom Coburn, R-Okla., and Jeff Sessions, R-Ala., did not vote.