The death of Justice Ruth Bader Ginsburg has put enormous new pressure on the two candidates in a presidential race already roiled by a global pandemic and a summer of civil unrest, raising the prospect of a contentious Senate confirmation battle waged side by side with the campaign. The skirmishing over a replacement is certain to thrust a constellation of red-hot issues — from abortion and gay rights to religious liberty and environmental regulation — to the foreground of national politics.
The Supreme Court may quickly become a shared focal point for the candidates in a contest that has unfolded, so far, as though the two parties inhabit different universes. Joseph R. Biden Jr., the Democratic nominee, has built a strong lead over President Trump by focusing on the president’s handling of the pandemic, while Mr. Trump has attempted to make up ground with dark and largely fictitious forecasts of looming insurrection by left-wing radicals.
The president signaled even before Justice Ginsburg’s death on Friday that he intended to inject judicial politics into the final stretch of the 2020 campaign. He released a new list of potential nominees earlier this month to motivate conservative voters who have grown demoralized during a year of political tribulations. But it was not clear that his right-wing coalition would be more motivated by a confirmation fight than the alliance of liberals and moderates supportive of Mr. Biden would be.
The former vice president has built a lead over Mr. Trump with lopsided support from women, people of color, moderates and college-educated whites — groups likelier to be alarmed than allured by the possibility of a court that tilts far to the right. Though he is well ahead of Mr. Trump in the polls, Mr. Biden has struggled to excite progressive voters and young people, who draw inspiration of a different kind from a far-reaching struggle over social policy and civil rights.
In a sign of the extraordinary stakes of the judicial struggle, former President Barack Obama issued a statement on Friday night calling on Republican lawmakers not to fill Justice Ginsburg’s seat. Alluding to Republicans’ claims in 2016 that he should not be allowed to replace a Supreme Court justice in an election year, Mr. Obama said it was “a basic principle of law” that even such “invented” standards be applied with consistency.
“The rule of law, the legitimacy of our courts, the fundamental workings of our democracy all depend on that basic principle,” Mr. Obama said. “As votes are already being cast in this election, Republican senators are now called to apply that standard.”
The likelihood of a polarizing fight to replace Justice Ginsburg seemed sure to command the attention of the candidates and the general public, perhaps unlike any other issue this election cycle besides the coronavirus that has ravaged the nation for the last six months. Senator Mitch McConnell, the Republican majority leader, vowed quickly on Friday night to bring a jurist chosen by Mr. Trump up for a vote.
For the most part, candidates up and down the ballot on Friday put out statements of mourning and tributes to Justice Ginsburg, rather than comments that explicitly staked out positions for a political fight. Mr. Trump was midway through a speech in Bemidji, Minn., when the announcement came of Justice Ginsburg’s death, but his advisers were relieved that the president had not learned of the news until after his speech was over, campaign aides said, because it meant he had not had to deliver an appropriate reaction in real time.
Hanging over the Republicans’ maneuvering is the emphatic argument by Mr. McConnell and his party, just four years ago, that Mr. Obama should not be allowed to name Judge Merrick B. Garland to a Supreme Court vacancy in the final year of his term.
Mr. Biden pointed to that precedent on Friday night as he paid tribute to Justice Ginsburg at the airport in New Castle, Del., after returning from a campaign trip to Minnesota.
“The voters should pick the president, and the president should pick the justice for the Senate to consider,” Mr. Biden told reporters, pointing to Republicans’ previous rhetoric to that effect and insisting, “That’s the position the United States Senate must take today.”
Two Republican senators have recently expressed serious misgivings about ramming through a Supreme Court appointment only a few months before the next president’s inauguration. The party holds 53 seats in the Senate, leaving relatively little room for defections, but only a few Republicans have ever broken with the party line on any matters of great importance.
Senator Susan Collins, Republican of Maine, told The Times in an interview this month that she would be uncomfortable with seating another justice in October. “I think that’s too close, I really do,” Ms. Collins said of a fall confirmation process.
Ms. Collins cast a crucial vote in the last Supreme Court battle that helped secure the confirmation of Justice Brett M. Kavanaugh, and she has faced backlash from voters in her current re-election fight.
Senator Lisa Murkowski of Alaska, a Republican who opposed Justice Kavanaugh’s nomination, told Alaska Public Radio on Friday that she was against confirming a new justice before the election. She took that position before Justice Ginsburg’s death was announced.
Even more than the presidential race, the campaign for control of the Senate could well be upended by a sudden focus on the Supreme Court, with uncertain consequences for both parties. Republicans are defending a large number of seats, including several in moderate and battleground states like Colorado, Arizona and North Carolina, where a vituperative confirmation process could be challenging for the party.
But Democrats have also been attempting to topple Republicans in Republican-leaning states, like Iowa and Montana, where conservative voters could embrace a court fight as the kind of enthusiastic cause that has so far eluded the G.O.P. in a largely downbeat election year. On Friday night, one Republican lawmaker in a difficult race, Senator Kelly Loeffler of Georgia, quickly encouraged Mr. Trump to pick a nominee before the election.
Several Democrats, including Senate Minority Leader Chuck Schumer and Senators Elizabeth Warren of Massachusetts and Tim Kaine of Virginia, took the opposite stand on Friday night, insisting that Mr. Trump must not be permitted to fill the seat.
In an unusual twist of political fate, the chairman of the Senate panel that would review a Supreme Court nomination, Senator Lindsey Graham of South Carolina, is facing the most difficult race of his career against Jaime Harrison, a former chairman of the state Democratic Party who has raised an enormous sum of money.
Mr. Graham said in a 2018 interview that if there were a Supreme Court vacancy in the last year of Mr. Trump’s term, he would not act on a nomination before the election. But he has not recently reaffirmed that pledge.
Ms. Collins is among the senators likeliest to face a painful squeeze at the ballot box as a result of Supreme Court politics. In a New York Times poll published on Friday, and conducted before Justice Ginsburg’s death, 55 percent of Maine voters said they disapproved of her vote to confirm Justice Kavanaugh. By a 22-point margin, voters in the state said they believed Mr. Biden would do a better job than Mr. Trump of choosing a Supreme Court justice.
By Saturday morning, Democratic advocacy groups were already targeting Ms. Collins with new, Supreme Court-themed advertising. NextGen America, an organization backed by the billionaire Tom Steyer, released an ad arguing that Americans’ “basic rights are in unprecedented danger” because of the vacancy and voters “can’t trust Susan Collins to do the right thing.”
Fix Our Senate, a Democratic-aligned group, unveiled its own ad campaign opposing a Trump appointment, while a third group, Demand Justice, said it would spend $10 million “to ensure no justice is confirmed before the January inauguration.”
In addition to Maine, Mr. Biden held an advantage on the Supreme Court issue in two other swing states, Arizona and North Carolina, by greatly varying margins, according to the Times poll. In Arizona, voters preferred Mr. Biden by 10 points on the issue, while North Carolinians favored him by a smaller gap of three percentage points.
Mr. Biden has said relatively little about the Supreme Court since securing the Democratic nomination last spring. He pledged during the primaries to make the first appointment of a Black woman to the Supreme Court, though he did not say whether that person would be his first nominee.
Unlike some of his rivals in the primaries, Mr. Biden never embraced proposals from the left to restructure or expand the Supreme Court in order to mute the impact of the two justices Mr. Trump has already appointed. But should Republicans proceed to fill Justice Ginsburg’s seat in a manner widely regarded as underhanded, Mr. Biden could face intense pressure from the progressive wing of the party to embrace those more drastic steps.
A former chairman of the Senate Judiciary Committee, Mr. Biden is himself a veteran of several bruising confirmation struggles, including the successful Democratic effort to thwart the nomination of Robert H. Bork in the 1980s and the process in 1991 that yielded the confirmation of Justice Clarence Thomas.
And Mr. Biden’s running mate, Senator Kamala Harris of California, sits on that same Senate panel, which would screen any nominee Mr. Trump submits for Senate approval.
Historically, Democratic strategists have complained of how difficult it is to rally Democratic voters’ support around a Supreme Court nomination. But given the polarizing issue of abortion and Justice Ginsburg’s status as a revered figure in the Democratic Party, that could prove different this year.
But on Friday night, conservative strategists were elated at the opportunity to ignite a new fire in a Republican base.
“There is no more incendiary event that could happen that hasn’t already happened this year,” Frank Cannon, a longtime social conservative activist, said, adding in a calendar-defying feat of hyperbole, “This is the largest October surprise that ever happened.”
But Mr. Cannon appeared to recognize, too, that a Supreme Court nomination could invigorate the left as well. For liberal voters, he said, “You see an illegitimate president who is stuffing a nominee through right before an election, and right after his party stopped another nominee a year before the last election.”
For all the immediate attention to an open Supreme Court seat and the death of a judicial titan, it was not clear that confirmation politics would truly seize and hold the attention of a country racked by infectious disease and economic devastation. With millions of Americans unemployed and tens of millions more struggling to return to work or send their children to school, much of the electorate may prioritize other matters when they fill out their ballots in the coming weeks or show up to vote in November.
And the presidential race, especially, has proved stubbornly stable despite all manner of tumult over the last few months. In the Times polls, the overwhelming majority of voters had firmly made up their minds about Mr. Trump and Mr. Biden. If a Supreme Court nomination were to shake up their thinking, it would be the first development in many months to do so.
Jeremy Peters and Annie Karni contributed reporting.