The Senate cleared a critical hurdle Monday on legislation banning discrimination against gays in the workplace, demonstrating the latest shift in a dramatic transformation of political views toward gay rights over the last decade.

Seven Republicans joined 54 members of the Democratic caucus Monday evening in a vote to formally begin consideration of the bill — virtually guaranteeing passage later this week -- on legislation that would prohibit discrimination in the workplace against gays.

More than 17 years since the last Senate votes on the issue, Monday’s initial victory demonstrated the fast moving attitudes on gay issues and the effort by lawmakers from both parties to catch up with the electorate, particularly younger voters who have far more liberal views on the issue.

To be sure, advocates still face long odds in getting the legislation to President Obama’s desk. House Speaker John A. Boehner (R-Ohio), whose caucus is dominated by lawmakers from districts where social conservatives control GOP primaries, reiterated his opposition Monday and declared that he would not bring the legislation to the House floor no matter the Senate outcome.

Supporters of the Employment Non-Discrimination Act noted that opponents such as Boehner have focused their critique of the bill as a gift to trial lawyers, shying away from the family values rhetoric that dominated past debates on gay rights.

On Monday, after seven years in the minority, Senate Republicans provided the key margin to advance the gay rights bill, along with a handful of Democrats from deep red states who a few years back might have feared the political backlash from supporting the legislation. In the hours leading up to the vote, the only Republicans to speak were those in favor of the legislation, including Sen. Mark Kirk (R-Ill.), who used his first Senate floor speech since suffering a stroke two years ago to support the bill.

Joining Kirk were Sens. Kelly Ayotte (R-N.H.), Susan Collins (R-Maine), Orrin Hatch (R-Utah), Dean Heller (R-Nev.), Rob Portman (R-Ohio) and Patrick Toomey. (R-Pa.)

The vote was delayed by several minutes as supporters of the measure scrambled to ensure at least 60 senators would vote to proceed with debate. Several senators alerted Majority Leader Harry M. Reid (D-Nev.) earlier Monday that they would be absent for the vote or returning late to Washington from weekend activities. Aides said that the anticipated number of absentee senators almost forced him to postpone the vote.

But Reid proceeded as scheduled and as the vote began, Ayotte, Portman and Toomey – the focus of an intense lobbying effort by gay rights groups in recent days -- headed to the Republican Cloak Room just off the Senate floor.

The vote proceeded for several minutes until senators realized that the trio were the last remaining senators present yet to vote. That prompted Collins, Jeff Flake (R-Ariz.) and the bills lead sponsor, Jeff Merkley (D-Ore.) to head to the cloak room in hopes of compelling them to emerge and vote.

After several more minutes, aides said Collins asked Reid and Sen. Charles E. Schumer (D-N.Y.) to come to the cloak room to speak with Ayotte, Portman and Toomey.

Aides familiar with the conversation said that Reid, Schumer and Merkley agreed to hold votes on two amendments authored by the three senators. The first by Ayotte and Portman would prevent state and local governments from taking legal action against religious groups that take advantage of the bill's religious exemption clause. The second amendment by Toomey would broaden the types of groups that are covered under the religious exemption clause. The Ayotte-Portman amendment will need to receive at least 50 votes to pass; the Toomey amendment will require 60, aides said.

Collins eventually shooed out the Democratic leaders and emerged later to signal that her colleagues would soon emerge to vote.

Ayotte emerged first, followed about five minutes later by Portman, then Toomey.

Formal debate on the measure is expected to begin on Tuesday.

The Senate this week will debate the first major gay rights legislation since Congress voted to repeal the military's "don't ask, don't tell" in late 2010. Congressional reporter Ed O'Keefe tells us what to watch for in the discussion surrounding the Employee Non-Discrimination Act. (The Washington Post)