(CNN) Republican and Democratic senators said Wednesday they expect a bill to codify same-sex marriage to eventually win the 60 votes needed to break a filibuster, a sign of growing public acceptance and a sea change over an issue that had once badly divided the two parties.
While most GOP senators are likely to vote against the bill, lawmakers in both parties believe there will be at least 10 Republicans who would join all 50 Democrats and advance the bill to a final up-or-down vote.
Buoyed by the 47 Republicans who voted for similar legislation that passed the House Tuesday, senators expected a similar show of bipartisan support when the measure hits the Senate floor.
One key Republican, Sen. Thom Tillis of North Carolina, told CNN Wednesday he "probably will" support the bill. And, importantly, Republican Whip John Thune said he expects the legislation will have similarly strong GOP support in the Senate as it got in the House.
"If and when (Democrats) bring a bill to the floor, we'll take a hard look at it," said Thune, a South Dakota Republican who cautioned he had not made a decision on the bill. "As you saw there was pretty good bipartisan support in the House yesterday and I expect there'd probably be the same thing you'd see in the Senate."
At this point, four Republicans, including Tillis, have signaled their support for the bill while several have said they will vote against it. A number of Republicans have not committed to how they will vote.
Senate Majority Leader Chuck Schumer, a Democrat from New York, said he wants to bring the bill to the floor soon, but did not announce when he would schedule a vote. He added that he was "impressed by how much bipartisan support the bill got in the House."
The Senate leaves for its August recess in two weeks, making it unlikely he will be able to get the floor time before then, especially as senators are already trying to pass a bill to boost production of semiconductor chips and a separate economic package. Taking it up after August moves the debate closer to the midterm elections and will allow Democrats to highlight what they believe are key social issues important to voters.
Thune, who said he respects the Supreme Court's 2015 decision in Obergefell v. Hodges that legalized same-sex unions, accused Democrats of forcing the issue to distract from high inflation and other economic problems that could hurt them in the midterm elections.
Marriage equality proponents are pressing to quickly pass the Respect for Marriage Act, which also legalizes interracial marriage, after Supreme Court Justice Clarence Thomas wrote in an opinion in the recent case that overturned the constitutional right to abortion that the high court might want to reconsider other decisions related to contraception and same sex marriage. Many Republicans have dismissed Thomas' words and said they don't expect the Supreme Court to revisit those cases.
Republican Sen. Rob Portman of Ohio, who is cosponsoring the bill, said holding a vote on this issue sends an "important message," and that it's "obvious" Republican views have changed over time.
"When you look at the House vote and you look at just the shifting sentiment about this issue," he said. "I think this is an issue that many Americans, regardless of political affiliation, feel has been resolved."
He noted that his "own personal views on this changed," over time. Portman publicly announced his support for same-sex marriage after his son came out a few years ago. Asked if they could get 10 Republicans to support the legislation, Portman referenced an anti-discrimination bill that the Senate was able to pass with 60 votes in the last few years. "I think there's a possibility of it, yeah."
In addition to Portman, GOP Sen. Susan Collins of Maine is a co-sponsor of the bill, as is Sen. Tammy Baldwin, a Wisconsin Democrat, the first known gay politician elected to the US Senate.
Speaking on the Senate floor, Schumer said he spoke to Baldwin and that "she is talking to Republicans to see where the support is."
Many Republicans have declined to state their positions on the legislation, saying they want to study the legislation first.
"I'm gonna take a look at what actually gets drafted, and we'll look at it at that point, but haven't got any comment until I see what it looks like," said Sen. Mitt Romney, a Republican from Utah.
"I'm gonna delay announcing anything on that issue until we see what the majority leader wants to put on the floor," echoed Senate Minority Leader Mitch McConnell, a Kentucky Republican, on Tuesday.
Other Republicans who would not commit their position included Sen. Richard Burr of North Carolina, Pat Toomey of Pennsylvania, Sen. Dan Sullivan of Alaska and Sen. Todd Young of Indiana.
Other Republican senators canvassed by CNN, including Sen. John Cornyn of Texas, Sen. Lindsey Graham of South Carolina and Sen. Marco Rubio of Florida, said they will vote against the House-passed bill.
Rubio dismissed the effort as a "stupid waste of time" as he walked onto an elevator where Baldwin was standing.
But GOP Sen. Lisa Murkowski, who is running for reelection in Alaska, said she would like to pass laws in the areas Thomas raised in his opinion to ensure abortion, the use of contraceptives, and same-sex marriage are legalized.
"I have suggested to others that not only would I like to see Roe, Casey, and Griswold on contraception codified but I've also made clear my support for, for gay marriage years ago," she said. "So I will look at what the House is doing and see what that might mean here on the Senate side."