Updated 11:49 a.m. | Sen. Dean Heller announced Monday morning that he supports the Employment Non-Discrimination Act, meaning that the lesbian, gay, bisexual and transgender civil rights measure is all but certain to have the 60 votes needed to thwart a filibuster.

“After listening to Nevadans concerns about this issue from a variety of viewpoints and after numerous conversations with my colleagues, I feel that supporting this legislation is the right thing to do,” Heller said in a statement.

The Senate is set to take a test vote on the legislation on Monday evening.

The Nevada Republican highlighted the existence of a similar law on the books in his home state.

“Under the leadership of this Governor, as well as the legislature over the past several years, Nevada has established a solid foundation of anti-discrimination laws,” Heller added. “This legislation raises the federal standards to match what we have come to expect in Nevada, which is that discrimination must not be tolerated under any circumstance.”

Heller’s senior Nevada colleague, Senate Majority Leader Harry Reid, had sounded optimistic in recent weeks about the chances for ENDA’s passage in the Senate.

A total of 21 states have laws similar to ENDA, which would block employment discrimination based on sexual orientation.

The measure already had 59 supporters before the Heller announcement, counting the GOP lawmakers who supported it at the committee level, so barring some change, the measure now has reached the magic number of 60.

Update 11:49 a.m.

The bill’s fate in the House has always been doubtful, and Speaker John A. Boehner, R-Ohio, made that more clear Monday morning.

“The Speaker believes this legislation will increase frivolous litigation and cost American jobs, especially small business jobs,” said Boehner spokesman Michael Steel.

A GOP aide noted that Boehner has long held the position that ENDA is bad legislation, and said the speaker believes gays and lesbians are already covered by existing employment law.

Correction:

An earlier version of this story included the incorrect number to states with laws barring employment discrimination based on sexual orientation. The number is 21.