Harris cancels in-person campaigning through Sunday after her communications director tests positive for the coronavirus.

The Biden campaign halted Senator Kamala Harris’s in-person campaigning through Sunday after two people who had traveled with her tested positive for the coronavirus, the campaign announced Thursday morning.

The communications director for Ms. Harris’s vice-presidential bid, Liz Allen, and a flight crew member tested positive, the campaign said. Ms. Harris herself tested negative on Wednesday.

“Senator Harris was not in close contact, as defined by the C.D.C., with either of these individuals during the two days prior to their positive tests; as such, there is no requirement for quarantine,” the Biden campaign manager, Jennifer O’Malley Dillon, said in a statement.

“Regardless, out of an abundance of caution and in line with our campaign’s commitment to the highest levels of precaution, we are canceling Senator Harris’s travel through Sunday.”

Ms. Harris had been scheduled to campaign in North Carolina on Thursday and in Ohio on Friday. She intends to return to the campaign trail Monday, the statement said.

“I will be transparent with you about any test results that I do receive,” Ms. Harris wrote on Twitter on Thursday. “In the meantime, remember: wear a mask, practice social distancing, and wash your hands regularly. It is possible to stop the spread.”

The campaign said it was also canceling travel on Thursday for Ms. Harris’s husband, Douglas Emhoff, but that he would resume campaigning on Friday.

The campaign has begun contact tracing, the statement said, “to notify everyone who came into contact with the individuals during the potential infection window.”

In a conference call with reporters, Ms. O’Malley Dillon said that Ms. Harris would be tested again on Thursday and that Joseph R. Biden Jr. would proceed with his schedule. He is slated to appear at a town hall event in Philadelphia that will be broadcast on ABC on Thursday night.

“He was not in close contact with either of these individuals,” Ms. O’Malley Dillon said.

The campaign said on Thursday afternoon that Mr. Biden had been tested for the virus on Wednesday night, and the results were negative.

Ms. Allen and the flight crew member were on a flight with Ms. Harris on Oct. 8, the day after the vice-presidential debate, Ms. O’Malley Dillon said in her statement. Mr. Biden and Ms. Harris campaigned together in Arizona that day but arrived in the state separately.

Ms. Allen and the flight crew member tested negative before the flight as well as after it, Ms. O’Malley Dillon said. In the past week, they “attended personal, non-campaign events,” she added, and were subsequently required to be tested. All other campaign staff members who were on the flight with them have tested negative multiple times since Oct. 8, she said.

The backlash from prominent Republicans against Facebook and Twitter for limiting or blocking the distribution of an unsubstantiated New York Post story on Hunter Biden grew on Thursday, as the Trump campaign said that Twitter had locked its account for trying to promote the article.

President Trump and several Republican senators condemned the social media companies’ decision to rein in distribution of the article, which discussed emails it claimed were obtained from a laptop that purportedly showed the business dealings of Joseph R. Biden Jr.’s son Hunter in Ukraine. The claims have not been verified.

Republican lawmakers were quick to call for investigations into why Twitter and Facebook had limited the spread of the article, with some calling it censorship. Senator Ted Cruz, a Republican of Texas, said that he planned to subpoena Twitter’s chief executive, Jack Dorsey, to discuss the decision.

“This is election interference and we’re 19 days out from an election,” Mr. Cruz said.

The Trump campaign said that Twitter had locked its official account after it attempted to promote the article. The campaign’s Twitter account, which uses the handle @TeamTrump and has 2.2 million followers, is separate from Mr. Trump’s personal account, which has more than 87 million followers. By Thursday afternoon, the account was restored, with the campaign tweeting a link to a livestream of Mr. Trump’s rally in North Carolina.

A Trump campaign spokesman, Tim Murtaugh, also accused Twitter of “election interference.”

A Twitter spokesperson on Thursday referred to a previous company response that said that the images in the Post’s article contained email addresses and phones, as well as hacked materials that violated Twitter’s rules for posting.

In an interview on Thursday with Fox Business, Mr. Trump said that he had not heard about Twitter’s actions involving his campaign. Then he said he was considering unspecified regulatory actions against social media companies and suggested he would go to court to force Twitter to reverse its actions.

“It’s going to all end up in a big lawsuit,” he said.

Mr. Trump spent Thursday morning retweeting supporters who decried the tech companies as censors.

In defiance of Twitter’s policy to prevent users from sharing the Post article, Republicans on the House Judiciary Committee also reproduced the article on its website on Wednesday and shared the link on Twitter. Twitter responded by blocking users from sharing the link, but then reversed the decision on Thursday, saying it had been an error.

“That decision has been reversed and the link is now unblocked,” a Twitter spokesman said.

On Thursday morning, the New York Post published a second story about Hunter Biden, including more images of emails. Twitter also blocked that link on its service, a company spokesman said.

President Trump and Joseph R. Biden Jr. were supposed to debate tonight. But Mr. Trump backed out after the Commission on Presidential Debates ruled that the event could be held only virtually, given the president’s coronavirus diagnosis.

The two men will instead engage in a Battle of the Town Halls, appearing in rival events on different networks. That’s a far cry from a debate, and most analysts assume that it’s unlikely to change minds. Mr. Trump’s supporters will presumably tune in to the president on NBC, while Mr. Biden’s supporters will check out their candidate on ABC. Since the appearances are at the same time, 8 p.m. Eastern, it will take a dedicated voter to attempt a compare-and-contrast.

What that means is that the third debate, in Nashville on Oct. 22, may be Mr. Trump’s last, best chance to change the course of a campaign that is moving against him. It is the final scheduled set piece, all but guaranteed to draw a huge audience and extensive coverage. Unlike, say, tonight.

Mr. Trump’s performance at the first debate was marked by his hectoring of Mr. Biden and the moderator, Chris Wallace, and was widely criticized. Polls suggest it cost him some support. From that perspective, Mr. Trump’s decision to pull out of the next one, rather than just engage Mr. Biden virtually, mystified members of both parties, particularly because Mr. Biden, given his polling lead, has little incentive to debate again.

Republicans had been hoping that tonight could be a mulligan. Now it’s down to Nashville.

“He needs a good debate, practicing common courtesy and restraint, and allowing Biden to speak,” said Charlie Black, a Republican consultant and veteran of presidential campaigns.

This not ideal for Mr. Trump. Historically, third debates do not have a major influence on the course of a campaign. By the time this one happens, Election Day will be less than two weeks away. Millions of people will already have voted.

Even if Mr. Trump heeds the advice of Republicans on changing his debate tone, there might not be enough undecided people in even that huge audience to make a difference.

President Trump and Senator Lindsey Graham have established clear but not overwhelming advantages in South Carolina, a heavily Republican state that is showing signs of competitiveness this year, according to a new New York Times/Siena College poll.

Mr. Trump leads Joseph R. Biden Jr., 49 percentage points to 41, while Mr. Graham, who is facing the most serious challenge of his career, is winning 46 percent of the vote compared with 40 percent for his Democratic rival, Jaime Harrison.

The New York Times /
Siena College poll

Donald Trump holds a clear lead over Joe Biden in South Carolina.

+14 Trump
55-41

+8 Trump
49-41

Based on a New York Times/Siena College poll of 605 likely voters in South Carolina from Oct. 9 to Oct. 15.

The Senate race, though, may be even more competitive because the survey finds that 12 percent of Black voters are undecided, which could favor Mr. Harrison, who is African-American. The poll has a margin of error of 4.5 percentage points.

No Democratic presidential candidate has carried South Carolina since Jimmy Carter in 1976, a streak that appears unlikely to be broken this year. But the combination of Black voters and white transplants there is poised to make the state more of a battleground than an afterthought going forward.

It’s this coalition of voters that’s pushing Mr. Trump’s advantage into single-digits, four years after he carried South Carolina by 14 points, and that has made the race between Mr. Graham and Mr. Harrison perhaps the most surprisingly close Senate matchup of 2020.

Still, South Carolina remains more conservative than its fast-changing neighbors, Georgia and North Carolina, and quite forbidding for Democrats. The state hasn’t elected a Democratic governor or senator since 1998.

While college-educated white voters in other Sun Belt states favor Mr. Biden or break even between the two presidential contenders, they favor Mr. Trump 50 percent to 38 percent in South Carolina. Even more stark, and for Democrats downright daunting, is the gap between white voters without a college degree: 77 percent favor Mr. Trump while just 18 percent support Mr. Biden.

Former President Barack Obama on Wednesday shrugged off President Trump’s calls for him to be prosecuted — and warned that the “insane” QAnon conspiracy theory movement was infiltrating the mainstream of the Republican Party and infecting public discourse.

Mr. Obama plans to hit the road on behalf of his former vice president, Joseph R. Biden Jr., over the next two weeks for socially-distanced appearances in battleground states to encourage Democrats during early voting, according to people familiar with his plans.

Mr. Obama gave a preview of his closing argument in his appearance Wednesday on “Pod Save America,” a popular podcast hosted by two of his former White House advisers, Jon Favreau and Tommy Vietor — appearing relaxed and tie-less, but stone-serious, in a Zoom interview.

Near the start, Mr. Vietor asked Mr. Obama what he thought about Mr. Trump “tweeting that the attorney general should indict you or indict Vice President Biden for spying on his campaign.”

Mr. Obama mimicked the response Republicans have often offered in response to Mr. Trump’s social media exploits: “Yeah. ‘I didn’t read the tweet’,” he replied.

He went on to discuss the larger implications of incendiary comments like Mr. Trump’s.

“One of the central foundation stones of a democracy is the idea that you do not, you do not allow the politicization of the criminal justice system, the intelligence system, the military. Right?” he said. “That is stuff that you keep out of politics right now. Because it’s too dangerous.”

He said an important question after the election, even if Mr. Biden wins, “is whether you start seeing the Republican Party restore some sense of, ‘Here are norms that we can’t breach,’ because he’s breached all of them,” Mr. Obama said of Mr. Trump. “They have not said to him, ‘This is too far.’”

Mr. Obama pointed to the increasing proliferation of candidates, including Mr. Trump, peddling baseless theories — most recently the debunked notion that the killing of Osama bin Laden was staged.

“When you look at insane conspiracy theories like QAnon seeping into the mainstream of the Republican Party, what that tells you is that there are no more guardrails within that media ecosystem,” he said. “How do we re-establish some baselines of truth?”

Drawing implicit comparisons with Mr. Trump, Mr. Obama said that in addition to having respect for institutions and expertise, Mr. Biden also had the character that voters should look for in presidents.

“Are they people who instinctively care about the underdog?” he asked. “Are they people who are able to see the world through somebody else’s eyes and stand in their shoes? Are they people who are instinctively generous in spirit? And that is who Joe is.”

Addressing listeners who would have preferred a more progressive candidate, Mr. Obama said that the first priority was to ensure Mr. Biden’s victory, but that they should continue to press their agenda after the election.

“The caution I always have for progressives,” he said, “is making sure that, as you push for the most you could get, that at a certain point you say, ‘All right, you know what? Let’s get this done and then let’s move on to fight another day.’”

Senator Lindsey Graham, a Republican in a tight re-election race in South Carolina, broke a law that forbids campaign fund-raising inside a federal building when he answered a reporter’s question after confirmation hearings for Judge Amy Coney Barrett on Wednesday.

Federal law forbids Senate members or staff from soliciting donations in federal buildings like the Hart Senate Office Building, where Mr. Graham is leading the hearings. In an interview shown on C-SPAN, the senator discussed fund-raising numbers and referred people to his website, saying, “If you want to help me close the gap, lindseygraham.com, a little bit goes a long way.”

Mr. Graham’s Democratic opponent, Jaime Harrison, raised a record $57 million from July to September, blowing away the previous quarterly record of $38 million. Mr. Graham raised $28 million in the same quarter, a record for Senate Republicans.

Kevin Bishop, a Graham campaign spokesman, told ABC News 4, a TV station in Charleston, S.C., that the senator was responding to a question about his campaign and fund-raising.

“Confident any reasonable person can see that any violation — if one even occurred — was unintentional and does not represent a pattern of behavior,” he said.

Campaigning on federal grounds, let alone fund-raising, is considered a potential ethics violation, but senators have not paid a high price when crossing the line. Other senators have made fund-raising statements similar to Mr. Graham’s with few consequences.

The voting rights group iVote announced Thursday that it would spend $10 million to defeat the Republican secretaries of state in Ohio and Georgia if they run for re-election in 2022, accusing both men of taking actions that reduce Black votes.

The group blamed Brad Raffensperger, the Georgia secretary of state, for presiding over a meltdown at polling places in the state’s June primary. And it said that the Ohio secretary of state, Frank LaRose, has made it harder for voters to drop off their ballots and vote absentee.

“If that’s the way you do your job, we’re coming for your job,” said Ellen Kurz, iVote’s president. Neither man has officially announced plans to run for re-election.

The group, iVote, a left-leaning organization, poured $3.6 million into a successful 2018 campaign supporting Katie Hobbs, the Democrat who was elected secretary of state in Arizona, Ms. Kurz said.

Recently, she said, her group’s war chest has grown as donors have become frustrated over what they see as efforts to minimize voter turnout, as well as increasing partisan behavior by some secretaries of state.

“We see the change in our small-donor operations and even with big donors reaching out to us,” she said. “We know we’re going to have the resources in 2022.”.

Maggie Sheehan, a spokeswoman for Mr. LaRose, said the facts did not support iVote’s premise. “It’s easy to vote in Ohio and successfully running the 2020 election is Secretary LaRose’s only focus,” she said, citing record registration and turnout.

Mr. Raffensperger’s office did not respond to requests for comment.

Mr. Raffensperger and Mr. LaRose both mounted well-funded campaigns in 2018, each spending more than $2.5 million in their election efforts.

There are 19 days until Election Day. Here are the schedules of the presidential and vice-presidential candidates for Thursday, Oct. 15. All times are Eastern time.

President Trump

1 p.m.: Holds a rally in Greenville, N.C.

8 p.m.: Participates in an NBC town hall event in Miami.

Former Vice President Joseph R. Biden Jr.

8 p.m.: Participates in an ABC town hall event in Philadelphia.

Vice President Mike Pence

12:30 p.m.: Visits the Memorial Cubano in Miami

Senator Kamala Harris

Events canceled.

Joseph R. Biden Jr.’s campaign announced raising $383 million in September, combined with the Democratic National Committee and their shared committees, and entered October with $432 million cash in the bank, his campaign announced on Wednesday.

“That’s more than I’ve raised in my whole life!” Mr. Biden marveled in a short video posted on Twitter on Wednesday evening.

The total means that Mr. Biden has raised nearly $750 million since Aug. 1, in back-to-back months of record-breaking hauls (he raised $364.5 million in August) that have delivered him a significant financial advantage over President Trump in the closing weeks of the campaign.

Mr. Biden has used those additional funds to spend more on television than Mr. Trump in the key battleground states and to stretch the map, with some ads now even airing in Texas.

That Mr. Biden would have a cash advantage over Mr. Trump was hard to imagine earlier this year. The former vice president had struggled to raise money online for most of the 2020 primary, and the president’s re-election campaign and the Republican National Committee entered April with a roughly $187 million edge over Mr. Biden and the D.N.C.

The reversal of financial fortunes is one of the more consequential developments of the general election.

Jennifer O’Malley Dillon, Mr. Biden’s campaign manager, said there were 1.1 million new donors in September and 5.5 million donors over all. She said that $203 million of the total had come online, about the same amount as in August. The biggest share came on the final day of September, the day after last month’s debate, when officials had previously said the campaign raised $24.1 million.

Mr. Biden had entered September with $466 million cash on hand combined with the D.N.C. and their joint operations, compared with $325 million for Mr. Trump and the Republican National Committee.

The Trump campaign has yet to announce its September fund-raising haul.

Joseph R. Biden Jr.’s campaign has introduced new digital and print ads aimed at mobilizing Puerto Rican voters in swing states. But the ads are not running in Florida or Pennsylvania, where Democrats are heavily targeting Puerto Ricans. They’re running in Puerto Rico.

The campaign hopes to build on the deep ties among the vast Puerto Rican diaspora, which outnumbers the roughly 3.2 million Puerto Ricans who live on the island. Those on the island cannot vote for president; those in the states can.

“Hazlo por mi,” the people in the ad urge their relatives and friends — do it for me.

Stateside candidates, especially in Florida, learned long ago that it was smart politics to buy advertising on Puerto Rican television networks that are also carried in Spanish-language cable in Orlando and Miami. Ahead of the 2018 midterms, Florida politicians made repeated trips to Puerto Rico to show their commitment to rebuilding after Hurricane Maria, which tore through the island in 2017.

The storm, which killed at least 2,975 people, exposed Puerto Rico’s dependence on a federal government that, under President Trump, has been very slow to release recovery aid. Mr. Trump, who also privately mused about selling the island, has nevertheless insisted, without irony, that he is “the best thing that ever happened to Puerto Rico.”

“The people of Puerto Rico know that their future is linked to what happens in the election,” former Representative Luis Gutiérrez, a Chicago Democrat who moved to Puerto Rico after his retirement, said from his home in Vega Alta. “When you talk to people here, Trump is on their lips all of the time.”

To try to blunt his unpopularity with Puerto Ricans, Mr. Trump has highlighted his endorsement from Gov. Wanda Vázquez. But she is in a weak position, having lost her primary in August.

On Tuesday, Mr. Biden made the front page of El Nuevo Día, Puerto Rico’s biggest newspaper, after giving the paper an interview as part of his campaign’s coordinated push for Puerto Rican voters.

“The traffic of information, of calls, between the Puerto Ricans who live in the United States and those on the island of Puerto Rico is constant,” Mr. Gutiérrez said. “You’re going to call your daughter anyway. You’re going to call your aunt anyway. Call them and say, ‘We need your help.’ We have so many issues that we are confronting on the island.”

The entertainment mogul Tyler Perry will help fund a $500,000 Black voter mobilization effort in Florida, continuing a growing trend of electoral involvement from Black celebrities and athletes ahead of the election.

Mr. Perry has partnered with Equal Ground Education Fund, a nonpartisan Florida group that works to increase Black voter engagement throughout the state. The effort, “Park & Praise,” which is to be formally announced today, will target 25 counties and 250,000 Black residents including in urban hubs such as Broward County and Miami-Dade County. The “Park & Praise” series will set up events where voters can drop off mail-in ballots while hearing from faith leaders, musical acts and gospel choirs.

The effort is an attempt to bring the “Souls to the Polls” model to the age of social distancing. In previous elections, churchgoing Black voters have been a reliable base for the Democratic Party, taking particular advantage of things like early voting after a Sunday service.

“Despite Florida’s historical disenfranchisement of Black voters, our voices will be heard whether we vote by mail or early,” said Jasmine Burney-Clark, the founder of the Equal Ground Education Fund. “Our work to provide robust voter education and ensure that accurate information reaches our communities is the highest priority and is exactly what this partnership with Tyler Perry is going to do.”

Mr. Perry is the latest Black celebrity to join efforts to get out the vote. Another campaign, led by the basketball superstar LeBron James, called “More Than a Vote,” is working to address the shortage of poll workers in Black communities in swing states.

The arrest of more than a dozen right-wing extremists who are accused of targeting the governors of Michigan and Virginia is only the latest example of threats of violence, in some cases egged on by President Trump, that loom over the final weeks of a historically divisive race.

In rural Iowa, Laura Hubka, the Democratic chair of Howard County, recently took out a concealed-carry gun permit after signs for Democratic candidates in her region were vandalized with bullet holes and she was personally threatened, she said.

In central Wisconsin, Tom Stepanek’s wife sat him down last month at the kitchen table and warned him that the president might not accept a peaceful transfer of power if he lost in November. “Are you sure you want to be doing this?” she asked her husband, who is the chair of the Waushara County Democrats and had also been threatened. “You’re going to be a target here,” she told him.

With polls showing the president behind Mr. Biden nationally and in key states, Mr. Trump has descended into rants about perceived enemies, both inside and outside his administration, triggering in his staunchest supporters such fears for the outcome — possibly a “stolen” election, maybe a coup by the far left — that he is emboldening them to disrupt the voting process, according to national security experts and law enforcement officials.

National security experts said that American elections are usually nonevents for law enforcement, and that transitions from one president to the next were typically a peaceful pageant of democracy.

“But not this year,” said Chuck Wexler, the executive director of the Police Executive Research Forum, who said that multiple police chiefs were extending patrol shifts in the weeks before Election Day. “This year is unlike any year.”

Ad Watch

With early voting well underway in most of the country, the cash-rich Biden campaign is turning to television ads as part of their get out the vote strategy, including this one, aimed at Black voters in Michigan.

The Message

Four young Black men gather next to a baseball field, hanging on the bleachers. Their tone is casual. “I can’t think of the last time it dawned on me to ask somebody, ‘Hey, bro, you registered? You know what I’m saying? Do you vote?’” one man says.

The conversation touches on the dire challenges facing the country, from taxes to vaccines, a casual version of “the stakes” that Joseph R. Biden Jr., the Democratic nominee, often invokes in his stump speech.

“We got to encourage our people to get out to vote man,” says another. “This basically isn’t an option.”

Fact Check

The ad makes no verifiable claims.

Where It’s Running

In Michigan.

The Takeaway

More than 1.1 million people in Michigan have already voted this year, and turnout is already at 25 percent of the total 2016 turnout. But in a state where President Trump won by under 11,000 votes in 2016, in part because the Black vote did not keep pace with turnout in 2008 or 2012, the Biden campaign is making a continued push to energize and turn out Black voters.

Using a television ad for a direct get out the vote message, an expensive medium rarely used for a task often left to on the ground operatives and digital tactics, is evidence of both the scale of those efforts and the sense that pandemic precautions have limited traditional door-knocking get-out-the-vote operations. And it highlights the need the Biden campaign sees in making greater inroads with Black voter turnout.

While President Trump hit the trail on Wednesday night in Des Moines, the Iowa Supreme Court ruled in his favor, determining that the state’s top election official had the authority to invalidate about 70,000 absentee ballot applications because they had been filled out in advance with voters’ personal information.

The ruling upheld a contentious directive by Secretary of State Paul D. Pate, a Republican, that required the applications to be blank when they were sent to voters.

Democrats and immigrant groups had challenged the constitutionality of the directive, which Mr. Pate used to nullify ballot requests from three counties.

Election officials in Linn, Johnson and Woodbury counties ignored the directive and sent out tens of thousands of applications to voters with their names, addresses, birth dates and voter personal identification numbers already filled out.

The wrangling over absentee ballots in Iowa came as polls showed a tight race between Mr. Trump and former Vice President Joseph R. Biden Jr. in the state, which Mr. Trump carried by nearly 10 percentage points in 2016.

Republicans had argued that the reinstatement of the applications would throw the election into chaos, but they were dealt a blow on Monday when a district court judge blocked Mr. Pate from enforcing the directive. The state Supreme Court granted a stay to Republicans on Tuesday that put the matter on hold until Wednesday’s ruling.

“I am glad the Iowa Supreme Court once again reaffirmed a commitment to election integrity,” Mr. Pate wrote Wednesday night on Twitter. “None of this voter confusion would have happened if not for the irresponsible and unlawful actions of the auditors in Johnson, Linn and Woodbury counties.”

It was not immediately clear whether Democrats would appeal the decision.

Tens of millions of voters are expected to rely on mail-in voting to avoid casting ballots in person because of the coronavirus pandemic. Republicans have mounted lawsuits in several states challenging deadlines for returning absentee ballots and the eligibility of voters. Their opposition has often echoed Mr. Trump’s unfounded claim that mail-in voting is rife with fraud.

Gov. Charlie Baker of Massachusetts would not commit on Wednesday to voting for President Trump in next month’s election, the latest hedge by a Republican officeholder who is not on the ballot this year.

The question of Mr. Baker’s allegiances came up during a news conference about the state budget and preparations for a second wave of coronavirus infections in the commonwealth.

Mr. Baker, whose embrace of mail-in voting has drawn the scorn of Mr. Trump, and who could be looking ahead to the 2022 governor’s contest in his deep-blue state, acknowledged that he was considering abstaining in the presidential election.

“You know, I think I may take a pass on that one,” Mr. Baker said.

The reservations of Mr. Baker were the latest example of some Republicans’ distancing themselves from Mr. Trump. This summer, the Democratic National Convention highlighted a number of prominent Republicans who are supporting Joseph R. Biden Jr., the Democratic presidential nominee. Some of Mr. Baker’s Republican predecessors in the Massachusetts governor’s office have also come out against Mr. Trump, including William F. Weld and Mitt Romney, who is now a senator representing Utah.

Mr. Trump derided Mr. Baker on Twitter last month as a “RINO,” a pejorative acronym that stands for “Republican In Name Only.” The barb came a day after Mr. Baker defended the integrity of mail-in voting, which the president has repeatedly claimed without evidence is rife with fraud.

“Mail-in balloting has been with us forever,” Mr. Baker said at the time.

In the same news conference on Sept. 24, Mr. Baker rebuked Mr. Trump over his continued refusal to commit to a peaceful transfer of power should the president lose the election to Mr. Biden.

“It is appalling and outrageous that anyone would suggest for a minute that if they lose an election they’re not going to leave, period,” Mr. Baker said.

Mr. Baker had previously bucked his party and the president after the death of Justice Ruth Bader Ginsburg when he urged Republicans to hold off making a nomination for her Supreme Court seat until after the election.

“The Supreme Court is too important to rush and must be removed from partisan political infighting,” he wrote on Twitter.