The high-stakes abortion battle looming over President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE’s next Supreme Court pick will likely be decided by two GOP senators: Susan Collins Susan Margaret CollinsClub for Growth to spend million in ads for Trump Supreme Court nominee Maryland's GOP governor says Republicans shouldn't rush SCOTUS vote before election The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November MORE of Maine and Lisa Murkowski Lisa Ann MurkowskiClub for Growth to spend million in ads for Trump Supreme Court nominee Pebble Mine CEO resigns over secretly recorded comments about government officials Maryland's GOP governor says Republicans shouldn't rush SCOTUS vote before election MORE of Alaska.

The two women are viewed as potential swing votes because they’ve made a series of high-profile breaks with their party over health care — voting against an ObamaCare repeal measure, a bill allowing states to deny Planned Parenthood federal family planning funding and legislation that would have banned abortion after 20 weeks.

ADVERTISEMENT

For Democrats to be able to sink Trump’s nominee — a major win in an election year — they’ll need to win over at least one GOP senator.

Republicans nixed the 60-vote filibuster for Supreme Court nominees, meaning they can be confirmed with a simple majority. With a 51-seat majority and Sen. John McCain (R-Ariz.) absent, Republicans have to keep their caucus united or pick up red-state Democrats if they want to get Trump’s pick confirmed.

Collins and Murkowski are already facing mounting pressure from both sides. So far, they have stopped short of taking firm positions on whether they would oppose a nominee viewed as anti-abortion or likely to overturn or chip away at Roe v. Wade.

Justice Anthony Kennedy’s announcement on Wednesday that he'll retire after 30 years on the bench roiled Washington and sparked questions and concerns about the future of Roe v. Wade, the landmark 1973 case that established a right to abortion.

Kennedy was the fifth vote in a 1992 case upholding that decision. And Democrats are seizing on the issue, which could help energize their voters heading into the November midterm elections.

Collins told reporters immediately following Kennedy’s announcement that she would prefer a moderate nominee.

“I view Roe v. Wade as being settled law,” she said. “It’s clearly precedent, and I always look for judges who respect precedent.”

When asked if she had any concerns about the likelihood of the nominee being a swing vote in any abortion-related cases, Collins said it was impossible for her to have concerns now because she doesn't know who the nominee is.

When asked a similar question, Murkowski sidestepped naming abortion rights as a deciding factor.

“I think it’s fair to say that on the limited occasions that I have had an opportunity to weigh in on a Supreme Court justice, it is scrutinizing every aspect of an individual,” she told reporters.

“Roe is one of those factor that I will weigh,” Murkowski added. “Is it the only factor that I weigh? No.”

Murkowski has drawn fire from Democrats and Republicans for her stance on abortion, and she was pressed on the issue during her 2016 reelection campaign.

“I do not like abortion," she said during a debate at the time. "But I recognize that the Supreme Court, through Roe v. Wade, has said that a woman has the right, that reproductive right, to choose, and I have supported that.”

The willingness of the two senators to buck the GOP on abortion, coupled with the party’s razor-thin margin in the Senate, makes them key votes for both sides.

Marc Short, the White House legislative affairs director, told reporters Thursday that Vice President Pence and White House staffers sat down with Collins and Murkowski before President Trump nominated Justice Neil Gorsuch.

"I think if you look back to the last nomination, there was an intentional effort to reach out and get their thoughts,” Short said. “And I would imagine that a similar process would happen this time."

White House legal counsel Don McGahn, one of the staffers who took part in the previous meetings, called Collins on Thursday to discuss the upcoming Supreme Court vacancy.

Collins and Murkowski were among six senators who met with Trump on Thursday evening to discuss the court vacancy, according to a statement from White House press secretary Sarah Huckabee Sanders.

Republicans have downplayed the importance of abortion in the upcoming nomination fight.

Sen. Jeff Flake Jeffrey (Jeff) Lane FlakeHow fast population growth made Arizona a swing state Jeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Republican former Michigan governor says he's voting for Biden MORE (Ariz.) said he wants a nominee who will abide by the Constitution, while Senate Majority Whip John Cornyn John CornynThe Hill's Campaign Report: GOP set to ask SCOTUS to limit mail-in voting Liberal super PAC launches ads targeting vulnerable GOP senators over SCOTUS fight Senate GOP faces pivotal moment on pick for Supreme Court MORE (Texas) predicted the caucus would stick together to confirm Trump’s pick.

“Every senator has got to make up their own mind,” Cornyn said when asked about Collins and Murkowski. “It is disqualifying, in my opinion, for someone to campaign for a federal judicial bench, including the Supreme Court, based on a political or partisan or ideological agenda.”

Democrats are already homing in on the two GOP senators, arguing they can’t claim to be for women’s reproductive rights and then support someone who would side against upholding Roe v. Wade.

“This is a legacy vote,” said Sen. Chris Murphy Christopher (Chris) Scott MurphyDemocratic senator calls for 'more flexible' medical supply chain to counter pandemics The Hill's 12:30 Report - Presented by Facebook - Don't expect a government check anytime soon GOP chairman to release interim report on Biden probe 'in about a week' MORE (D-Conn.). “I don’t think you can say you’re pro-choice if you cast a vote that will be looked upon as the one that criminalized abortion.”

Sen. Amy Klobuchar Amy KlobucharSocial media platforms put muscle into National Voter Registration Day Battle lines drawn on precedent in Supreme Court fight Sunday shows - Ruth Bader Ginsburg's death dominates MORE (D-Minn.), a member of the Judiciary Committee, said the upcoming Supreme Court fight “will be a very big moment” for Collins and Murkowski.

Democrats are getting help from outside progressive groups who are urging voters to immediately begin efforts to sway Collins and Murkowski.

"We have had support in the past from Sens. Collins and Murkowski around the defunding of Planned Parenthood, around the protection of Roe v. Wade, and we believe that is a very important piece of this puzzle,” said Dawn Laguens, executive vice president for Planned Parenthood.

Jessie Hellmann contributed. Updated at 9:53 p.m. EDT.