WASHINGTON — Hours after the Supreme Court announced the death of Justice Ruth Bader Ginsburg on Friday, Senator Mitch McConnell of Kentucky, the majority leader, vowed that the Senate would vote on a replacement named by President Trump, setting up what is all but guaranteed to be a heated fight over the nation’s highest court that carries heavy political consequences.
That statement answered the question of whether Mr. McConnell, who in 2016 blocked President Barack Obama’s Supreme Court nominee because it was an election year, would dare try to confirm one named by Mr. Trump so close to an election. He would. Now the question is, can Mr. McConnell pull it off?
The process is likely to be ugly, but it can be done. Here’s how it works.
Can Democrats block Trump’s nominee through a filibuster?
Democrats eliminated the 60-vote threshold for most judicial nominees in 2013, frustrated by Republicans’ use of the filibuster to slow and impede Mr. Obama’s agenda. In turn, angered by resistance to the nomination of Justice Neil M. Gorsuch in 2017, Republicans abolished the limitation on Supreme Court nominees, further whittling down the scope of the filibuster.
As a result, Mr. McConnell could bring the nomination to the Senate floor and approve it with a simple majority vote. Mr. Trump signaled on Saturday that he would formally name someone to fill the vacancy in the near future.
“We have this obligation, without delay!” he tweeted, referring to the selection of justices.
It remained unclear, however, whether Mr. McConnell, himself up for re-election along with a handful of vulnerable Republican incumbents, would try to advance the nomination before Election Day. He could also opt to do so in a lame-duck congressional session after Nov. 3.
Does McConnell have the votes to confirm a nominee?
Because Republican hold a slim majority — 53 to 47 — Democrats would need only four Republicans to join them in opposition to sink the nominee. (In the case of a tie, Vice President Mike Pence, in his role as president of the Senate, would cast the tiebreaking vote.)
Though Mr. McConnell vowed that the Senate would vote on Mr. Trump’s chosen nominee, he notably made no mention of when that would occur — a signal that he was weighing the political calculus for the handful of vulnerable Republican senators facing tough races.
Given Mr. McConnell’s decision to refuse so much as a hearing for Judge Merrick B. Garland, Mr. Obama’s pick to succeed Justice Antonin Scalia in 2016, a handful of Republicans have signaled a desire to wait until after Election Day to approve a nomination. It is unclear, however, what objections remain to approving a nomination in the lame-duck session between November and the start of a new Congress in January.
Which Republicans might defect?
Senator Susan Collins of Maine, one of the most vulnerable Republicans facing voters this year,said on Saturday that while she would not object to President Trump naming a successor to the post, she did not believe the Senate should vote on confirmation before Election Day.
Ultimately, she said in the statement, she believed the vacancy should be filled by the winner of the presidential election.
“In fairness to the American people, who will either be re-electing the president or selecting a new one, the decision on a lifetime appointment to the Supreme Court should be made by the president who is elected on November 3rd,” Ms. Collins said.
Senator Lisa Murkowski of Alaska told a local radio station in an interview before Justice Ginsburg’s death was announced that she would not vote to confirm a Supreme Court nominee before Election Day.
Senator Mitt Romney of Utah has not indicated how he might regard an election-season confirmation push, but he has established himself as one of the few Republicans willing to break with Mr. Trump, most notably at his impeachment trial, when he voted to convict the president and remove him from office.
Senator Charles E. Grassley of Iowa, a former chairman of the Judiciary Committee, previously said that he would not conduct Supreme Court confirmation hearings in a presidential election year given his party’s blockade of Judge Garland, but he no longer controls the panel.
Senator Lindsey Graham of South Carolina, the current judiciary panel chairman, also said in 2016 that a Supreme Court vacancy occurring in the last year of a president’s term should not be filled until after the election. But on Saturday, he reversed himself, saying the bruising battle over Justice Brett M. Kavanaugh’s confirmation had changed his mind.
“I will support President @realDonaldTrump in any effort to move forward regarding the recent vacancy created by the passing of Justice Ginsburg,” he wrote on Twitter.
What effect will the election have on the vacancy?
The proximity of the election was already weighing heavily in Republicans’ planning for the confirmation process and its timing.
Ms. Collins is facing the toughest race of her career in Maine, in part because of her 2018 vote to confirm Justice Kavanaugh, and her political challenges in a state where Mr. Trump is deeply unpopular are likely to stiffen her resistance to a quick confirmation.
On the other end of the spectrum, several Republicans, including Mr. Graham, are facing difficult re-election races in conservative states where Mr. Trump is revered by the party, and they are spoiling for an election-season fight that can demonstrate their loyalty to the president and activate conservatives.
For many Republicans, the ülkü situation might be to begin the confirmation process quickly, injecting it into the political bloodstream but waiting until after Election Day — when vulnerable incumbents no longer have to worry about being cast out by angry voters — to hold a confirmation vote.
Mr. McConnell, who is also up for re-election, counseled his members to avoid stating a position on how they would handle the vacancy, as he privately gauges how to time any confirmation fight for maximum political advantage.
“This is not the time to prematurely lock yourselves into a position you may later regret,” Mr. McConnell wrote late Friday night after Justice Ginsburg’s death was announced. “I urge you all to be cautious and keep your powder dry until we return to Washington.”
Mr. McConnell’s majority could narrow even further if Mark Kelly, the Democratic nominee for Senate in Arizona, defeats Senator Martha McSally, the Republican incumbent, and is seated before January 2021. Because Ms. McSally was appointed to her seat and began serving last year, the race is a special election. Mr. Kelly could be sworn in as early as Nov. 30.
On Friday, Republican and Democratic election lawyers told The Arizona Republic that such an outcome was possible.
What if Republicans lose the White House, the Senate or both? Could they still confirm Trump’s nominee after the election?
Congress typically reconvenes after Election Day for what is known as a lame-duck session, when lawmakers act on unfinished business before adjourning for the year. Since the newly elected members would not be seated until the new Congress convened in January, the partisan breakdown during this period would be unchanged from what it is now, meaning that Republicans would remain in control of the Senate even if they had lost their majority. Similarly, if he were to lose on Election Day, Mr. Trump would remain president until former Vice President Joseph R. Biden Jr. was sworn in in January.
That means that even if Mr. Biden won the presidency and Democrats secured control of the Senate, Mr. McConnell would remain majority leader for the remainder of the year, with the ability to force votes provided that he maintained the support of a simple majority. Given his zeal for filling the federal courts with conservative jurists, Mr. McConnell would almost certainly avail himself of the opportunity to do so to confirm a Supreme Court justice.
Nicholas Fandos contributed reporting.