The death of Supreme Court Justice Ruth Bader Ginsburg has injected new uncertainty into the legal battle over how Americans will vote during the coronavirus pandemic, as liberals mourn a powerful champion for voting rights and partisans on both sides consider how a more conservative court might act if drawn into a contested presidential race.

The vacancy left by Ginsburg, the high court’s second-ever female justice and leader of its liberal wing, came just over six weeks before the election — a critical point in a campaign already defined by hundreds of lawsuits over voting rules and an outsize role for the courts in determining how ballots are distributed, cast and counted.

As Democrats and voting rights advocates seek to lower barriers to voting during the pandemic, the Supreme Court has largely deferred to local and state officials, showing a reluctance to upend rules close to the election.

Legal experts disagree about whether the blizzard of election-related lawsuits this year makes it more or less likely that the Supreme Court could end up playing a role in determining the winner of the presidential race, as it effectively did after Florida’s election meltdown in 2000.

The fact that key issues such as ballot postmarks and witness requirements are being hashed out now in lower courts makes the possibility more remote, some said.

But others noted the massive increase in the number of Americans expected to vote by mail — many for the first time — and said possible errors by those voters will open the door to more lawsuits with potential to rise to the high court.

“That will create an opportunity for post-election litigation over what the rules mean, are those ballots really invalid,” among other questions, said Michael T. Morley, who teaches election law at Florida State University’s law school.

Even if a pivotal election case ended up before the justices, concerns about preserving the court’s reputation and safeguarding public trust in the election outcome — as well as the shadow of the 2000 presidential race — could outweigh pure ideological divisions, veteran litigators said.

“All members of the court are aware of the reputational fallout of Bush v. Gore,” said attorney David Boies, who represented Vice President Al Gore in the 2000 case that has become symbolic of a more politicized court. “A number of the Republicans on the court are, I think, very committed to the integrity and the legacy of the Supreme Court and do not want to see it damaged again by the perception that it is involving itself in partisan politics. The chances that the Supreme Court would involve itself are limited.”

Ginsburg’s death leaves the court with just eight justices headed into Election Day, as it had four years ago, but this time with a more conservative tilt — five justices nominated by Republican presidents and three nominated by Democrats.

President Trump has said he plans to nominate someone to the open seat later this week. If Senate Republicans confirm that person, the court will have an even more pronounced 6-to-3 split favoring conservatives in closely divided cases. A Trump nominee, his third, could limit the central role of Chief Justice John G. Roberts Jr., who has sided with the liberal wing of the bench at times, countering the administration.

The president has indicated that he expects the courts to play a defining role in the election — by declaring a winner on election night, long before most mail ballots have been counted.

“We’re going to have a victory on November 3rd the likes of which you’ve never seen,” Trump said at a rally in Fayetteville, N.C., on Saturday night. “Now, we’re counting on the federal court system to make it so that we can actually have an evening where we know who wins, not where the votes are going to be counted a week later or two weeks later.”

Still, the chance that the election ends up hinging on a case that goes before the nation’s highest court is a “black-swan scenario” or a “royal straight flush in Vegas — you’re not banking on those odds,” said Justin Levitt, a professor at Loyola Law School who closely follows voting rights litigation.

“There is always a fight in the courts about whether to count certain ballots or not and under what conditions,” Levitt said. “It is really rare that those fights are dispositive. It’s even rarer in a presidential election, and there’s a world of difference between lots of lawyers having lots of stuff to file and, ‘Oh my God, 4-4 in the Supreme Court.’ ”

Battle lines drawn

Demands for an immediate election result have become a refrain for the president, who regularly makes unsubstantiated claims that mail ballots lead to widespread voter fraud, even as his campaign encourages supporters in swing states to embrace the practice. (Trump has also voted by mail, casting a Florida ballot from Washington through an absentee process twice this year.)

In court, Trump’s reelection campaign and the Republican National Committee have filed suit or intervened in cases with the goal of stopping voting rules from changing as a result of the pandemic.

Meanwhile, Democrats and voting rights advocates have sought to make it easier for voters to cast mail ballots this year, pushing for paid return postage for ballots, more voter-friendly signature-matching rules and deadlines that allow ballots postmarked by Election Day but received afterward to count, among other priorities.

Those competing efforts have helped drive an unprecedented number of suits related to elections and voting filed throughout the country this year — more than 300 in 44 states, according to one count.

Several cases have already risen to the high court, including disputes about witness rules for mail ballots in two states. Several more could follow the same path before Election Day, including a dispute over voting rights for felons in Florida that was recently before the U.S. Court of Appeals for the 11th Circuit and a fight over whether to relax absentee voting rules in Texas that was recently before a three-judge panel of the 5th Circuit.

How Ginsburg’s absence could affect any cases in the near term remains to be seen.

Marc Elias, who is leading litigation efforts for Democrats, declined to speculate. He noted that in one of her final dissents, in a 5-to-4 case where conservative justices blocked a plan for extended absentee voting in Wisconsin’s April primary, Ginsburg wrote, “Ensuring an opportunity for the people of Wisconsin to exercise their votes should be our paramount concern.”

“Justice Ginsburg was a towering figure in so many areas of the law, but particularly in the area of voting rights,” Elias said. “She understood that the courts are there to protect the voters and that that’s the thing that matters more than anything else.” He added: “She understood that elections are first and foremost about ensuring voters’ ability to vote and that everything else comes after that. We will miss that voice, that clarity, on the court in the future.”

Mandi Merritt, a spokeswoman for the Republican National Committee, said in a statement using a Joe Biden quote from 2016: “ ‘The American people deserve a fully-staffed court of nine.’ Those are Joe Biden’s words, and we agree, particularly in a crucial election year. The RNC will continue the fight to protect voter integrity so that voters can have confidence in a free, fair and transparent election.”

Even with Ginsburg on the bench, the court largely took a cautious approach this year to changing voting rules and deferred to local officials, as it showed in two cases this summer.

In July, the justices ruled 5 to 4 that Alabama did not have to abide by a lower court’s decision to lift strict rules for how to cast a mail ballot in three counties, such as a requirement to submit a photocopy of identification with the ballot. The court’s conservatives were in the majority, and liberal justices who dissented did not provide an explanation for their votes.

That ruling was a victory for Republicans. But in August, the court handed a win to Democrats in a similar case in Rhode Island, denying the GOP’s effort to preserve a requirement that voters obtain signatures from two witnesses or a notary to validate their mail ballots. The state had already agreed in a consent decree not to enforce the rule.

While a vote tally was not announced, Justices Clarence Thomas, Samuel A. Alito Jr. and Neil M. Gorsuch indicated they would have granted the stay requested by Republicans.

Earlier in the year, when the court intervened in the Wisconsin primary and overrode a plan by the Democratic governor to extend absentee voting for one week, its narrow decision had far-reaching reverberations.

In that case, the court split 5 to 4 along ideological lines to stop Gov. Tony Evers’s plan, rejecting pleas from Democrats who said thousands of voters would be disenfranchised or forced to vote in person during an early peak in the coronavirus crisis.

The majority opinion said Evers’s plan for extended voting was “extraordinary relief and would fundamentally alter the nature of the election.” The justices emphasized that the relief was more than had been asked for by Democrats and liberal groups.

Ginsburg wrote the dissent for the four liberal justices, saying it “boggles the mind” that the majority was trying to apply the court’s rules as usual during a pandemic.

“While I do not doubt the good faith of my colleagues, the court’s order, I fear, will result in massive disenfranchisement,” she wrote.

While the ruling was seen initially as a decisive win for Republicans, the court also ordered that absentee ballots count if they were postmarked by the day of the election but received within a certain time frame.

As a result, tens of thousands of mail ballots that arrived after the April 7 presidential primaries and spring elections were counted by local officials, a review by The Washington Post found. Democrats later cited the ruling in separate litigation over postmark deadlines.

Challenge for the court

Since Ginsburg’s death Friday, some Republicans have used the possibility of a 4-to-4 deadlock on voting issues after the election as an argument to support confirming Trump’s soon-to-be-announced nominee.

“Democrats and Joe Biden have made clear they intend to challenge this election,” Sen. Ted Cruz (R-Tex.) said that night on Fox News. “They intend to fight the legitimacy of the election. . . . We cannot have Election Day come and go with a 4-4 court that is equally divided and cannot decide anything.”

In 2016, when President Barack Obama nominated Merrick Garland to the high court after the February death of Justice Antonin Scalia, Cruz was among the Republicans who did not take issue with the idea of a 4-to-4 split on the court. In such a case, lower-court decisions stand.

Senate Majority Leader Mitch McConnell (R-Ky.) blocked Garland’s consideration, arguing that Obama should not be permitted to fill the seat in an election year — a position he reversed with Trump in the White House.

The potential for a decision like Bush v. Gore looms large under the circumstances. In that case, the court ruled 7 to 2 to end the recount of Florida’s votes. The justices also split 5 to 4 along ideological lines in deciding there was no alternative recount that could be completed by the deadline.

Only two justices who were involved remain on the court: Clarence Thomas, who sided with conservatives in concluding that Florida’s recount process violated the Constitution’s guarantee of equal protection and that the only remedy was to halt the process, and Stephen G. Breyer, now the most senior of the court’s liberals, who agreed with the majority holding that the recount was improper but also issued a separate dissent, arguing that a new constitutional recount was possible.

It was Justice John Paul Stevens, joined by Ginsburg and Breyer, who issued a stinging dissent, warning that the court risked damaging its reputation for operating above the partisan fray and that the majority “can only lend credence to the most cynical appraisal of the work of judges throughout the land.”

“Time will one day heal the wound to that confidence that will be inflicted by today’s decision,” Stevens wrote. “One thing, however, is certain. Although we may never know with complete certainty the identity of the winner of this year’s Presidential election, the identity of the loser is perfectly clear. It is the Nation’s confidence in the judge as an impartial guardian of the rule of law.”

Roberts, nominated by President George W. Bush in 2005, has since emerged as the pivotal center of the bench. The chief justice has repeatedly shown an interest in moderation by the court and strengthening the public’s sense of its impartiality, crafting rulings that forgo strict conservative ideology or partisan absolutes.

Roberts may have another opportunity to exercise this prerogative after the election, when a second wave of voting litigation could bring a pivotal case or cases to the high court.

The overwhelming factor likely to determine what happens in court is just how close the results are on Election Day, Florida State’s Morley said. If the margin is tight in a small number of jurisdictions because of complications arising from the pandemic or a large number of problematic absentee ballots, Morley said, he expects “the litigation to be aggressive and to continue right up until the votes are cast in the electoral college and quite possibly beyond.”

Other experts said that even if the margins are very close, it is unlikely that the court will be forced or agree to rule in a way that decides the winner of the election.

“The mood is angry and litigious, and there will be a lot of noise and paper after the election, but probably more noise than paper,” Levitt said, referring to legal action. “A lot of the issues that people would be fighting about, they’re fighting about now, and the courts have given their answers. The courts aren’t going to be all that willing to say, ‘Let’s take another look at this.’ ”

Boies said that the election cases percolating ahead of November involve state, not federal, law and that disputes over whether mail-in ballots are valid are typically resolved by local canvassing boards or state courts.

Even so, Boies said, “there will be much more attention and controversy about it because of the importance of this election.”

Myrna Pérez, director of the Voting Rights and Elections Program at the Brennan Center for Justice, said she is more concerned about what voters will experience on the ground than hypothetical scenarios about what might come after that.

“I think if we’re getting to the point where it’s going to the courts, it means something else in our system didn’t work the way it should have,” she said.

Pérez said Ginsburg’s absence will be acutely felt, regardless of the outcome.

“She had this gift of being able to take these legal principles and put them in a very concrete and understandable way,” she said. “. . . She was a person who inspired institutional faith in the court.”

CORRECTION: A previous version of this post incorrectly said that Justice Ruth Bader Ginsburg wrote the dissenting opinion in Bush v. Gore. Justice John Paul Stevens wrote the opinion.