The U.S. Senate invoked a motion for cloture this afternoon, 61 to 30, just one vote more than the 60 it needed to force the chamber to take up debate and consideration of the Employment Non-Discrimination Act (ENDA).

It is not clear whether the Senate will begin debate tonight or later this week, but its passage seems almost certain, given that the procedural vote drew at least eight Republicans to join Democrats and Independents to support its movement to the floor.

The bill seeks to prohibit negative employment actions against employees or applicants due to their sexual orientation and/or gender identity. (To watch Senate action tonight, go to C-SPAN 2 or c-span.org.)

Even before the Senate convened, The Hill newspaper predicted ENDA would move to the floor thanks to an announcement Monday morning by Republican Senator Dean Heller of Nevada that he would support the measure.

But House Speaker John Boehner also made clear Monday morning that he had no intention of allowing ENDA to the House floor. Through a spokesman, he said ENDA would increase “frivolous litigation and cost American jobs.” The comments were not a surprise; Boehner has said previously that “There are ample laws already in place” to deal with workplace discrimination.

President Obama’s Organizing for America group says there are 29 states where there are no laws protecting employees from discrimination based on sexual orientation or gender identity. They include Alaska, Alabama, Arkansas, Arizona, Florida, Georgia, Idaho, Indiana, Kansas, Kentucky, Louisiana, Michigan, Missouri, Mississippi, Montana, Nebraska, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, and Wyoming.

In addition to his own essay in support of ENDA, published Sunday night at huffingtonpost.com, President Obama’s organization sent out an e-mail to its supporters asking them to sign a petition for the measure.

Senate Majority Leader Reid said the existing “patchwork” of state laws prohibiting sexual orientation and gender identity discrimination is not good enough. He said House Speaker Boehner should take his cue from 56 percent of Republicans nationally who do support ENDA. And 81 percent of all Americans approve the measure.

Senator Tom Harkin (D-Iowa), who has championed the bill in his Senate Committee on Health, Education, Labor & Pensions (HELP). Harkin said more than 56 percent of Americans live in states that give “no recourse under law” for discrimination based on sexual orientation.

Harkin credited Senate sponsor Jeff Merkley (D-Ore.) and Mark Kirk (R-Ill.) for mustering the 60 votes the bill needs to pass the motion to put it on the floor and championing it. Harkin likened consideration of ENDA to that of the Civil Rights Act of 1964 and the 1990 Americans with Disabilities Act.

“Here we are taking one more step to make the American family more inclusive,” said an enthusiastic Harkin. “…This is an historic step for the United States Senate to do today.”

Senator Tammy Baldwin (D-Wisc.), the senate’s only openly LGBT member, offered remarks before the cloture vote. She noted that Wisconsin, 20 states, and the District of Columbia have laws that prohibit discrimination against gays and lesbians but that “in over two dozen states it is legal to discriminate against LGBT employees.”

“That is simply wrong,” said Baldwin, “and this legislation seeks to right that wrong.”

Before today’s vote, the Senate mustered 60 votes for 71 percent of the cloture motions it has faced this year. It failed to pass two such motions (on judicial nominees) last week.

Twenty-five Republicans voted for a cloture motion that allowed the Senate to pass a continuing resolution to fund the government without defunding the Affordable Care Act.

ENDA got its first and only U.S. Senate vote in 1996, when it failed 49 to 50 (one senator had to be out of town on an emergency). The Republicans held a four-vote majority.

It has passed the House one time, in September 2007, on a vote of 235 to 184. Democrats had a 35-vote majority at the time.

The text of this year’s bill is the same as it was in 2011, covering both sexual orientation and gender identity. The bill also makes clear that employers may require employees to adhere to “reasonable dress or grooming standards…provided that the employer permits any employee who has undergone gender transition prior to the time of employment, and any employee who has notified the employer that the employee has undergone or is undergoing gender transition after the time of employment, to adhere to the same dress or grooming standards as apply for the gender to which the employee has transitioned or is transitioning.”