News of Justice Ginsburg’s death broke just minutes after Mr. Trump took the stage at a rally in Bemidji, Minn., where he made no mention of her passing, even as he bragged about his record of appointing conservative judges and noted that he had named Senator Ted Cruz of Texas as a potential Supreme Court nominee.
For almost two hours, the president riffed onstage, at times discussing the importance of the judicial nominations, even as he appeared to be the only person in the airport hangar still in the dark. “The next president will get one, two, three or four Supreme Court justices,” he said. “I had two.”
Someone in the audience yelled “Ginsburg is dead!” but Mr. Trump did not appear to hear the cry, or react.
Instead, he remained unaware of the potentially seismic shift to the balance of the court that had occurred while he was launching sexist attacks against Hillary Clinton and stoking fears of a flood of Islamic terrorists that would occur if Joseph R. Biden Jr. were elected.
Mr. Trump, who prides himself on being able to change cable news chyrons and news cycles with a tweet or an aside at a rally, was delivering an extended performance totally in the dark about one of the biggest news events of the campaign. Even after his own chief of staff, Mark Meadows, had released a statement on Twitter, Mr. Trump was still onstage, taking a poll about what nickname his supporters liked better for Mr. Biden.
He was informed by reporters after the rally, before boarding Air Force One to return to Washington. “She led an amazing life,” he said. “What else can you say? She was an amazing woman — whether you agree or not — she was an amazing woman who led an amazing life.”
Mr. Biden was flying back to Delaware after making his own visit to Minnesota, where he gave a speech at a carpenters’ training center in Hermantown, a suburb of Duluth.
The death of Ms. Ginsburg upended what had been a relatively conventional day on an unconventional campaign trail. Mr. Biden and Mr. Trump had both turned their attention on Friday to Minnesota, where victory barely eluded Mr. Trump four years ago, with dueling events on the first day of in-person early voting in the state.
Mr. Trump called his largely maskless rally at the Bemidji airport a “protest against stupidity” and portrayed himself as the one thing protecting Minnesota from a flood of “radical Islamic terrorists” that he claimed wanted to infiltrate the state.
“I am your wall,” he said, “between the American dream and chaos.”
Later, he noted that “one of the things we have done that is so good with the Supreme Court,” adding: “We have two Supreme Court justices.” He made no mention of what will inevitably be a partisan battle about whether or not Mr. Trump can appoint a third Supreme Court justice in the six weeks before the election.
Instead, he delivered a typically discursive performance in a state that he has long been determined to flip. On Friday night, speaking outside a small city in the northern part of the state, Mr. Trump leaned into the state’s urban-rural divide by stoking fears about immigrants flooding urban settings if he loses, and claiming, inaccurately, that Democrats wanted to get rid of the police force in Minneapolis.
“Sleepy Joe will turn Minnesota into a refugee camp,” Mr. Trump claimed, making the alarmist claim that Democrats would “open the floodgates to radical Islamic terrorists.”
Mr. Trump also launched into a string of sexist attacks against women who are not running for president. He noted that Mrs. Clinton, the 2016 Democratic nominee, was not “big into yoga,” which she claimed was the subject of many of her deleted emails on her personal server. “If she is, she is not getting her money’s worth,” he said, prompting vintage chants of “Lock Her Up” that the president did nothing to quell.
He also accused Representative Alexandria Ocasio-Cortez of New York of spending $2 million on “dresses” and rent, and resuscitated an inaccurate story about Representative Ilhan Omar of Minnesota marrying her brother.
The competing campaign events on Friday came in a state where Mr. Trump is going on the offensive, even as he simultaneously plays defense in a number of critical battlegrounds, including neighboring Wisconsin. In 2016, Mr. Trump lost Minnesota to Mrs. Clinton by only 1.5 percentage points, or about 45,000 votes, and the Trump campaign is targeting the state as a pickup opportunity this time around.
But no Republican presidential candidate has won Minnesota since President Richard M. Nixon’s re-election in 1972, and Mr. Biden appears to be in a substantially stronger position in the state than Mrs. Clinton was, with time running out for Mr. Trump to improve his fortunes. Mr. Biden held a nine-point lead among likely voters in a poll conducted this month by The New York Times and Siena College.
The visits by Mr. Biden and Mr. Trump also offered another reminder of the starkly different approach the two candidates are taking to campaigning in a pandemic. Unlike Mr. Trump, Mr. Biden is not holding rallies, and his speech was not open to the public.
In his speech, Mr. Biden struck a populist tone, leaning on his middle-class roots and sketching a picture of a Trump presidency where billionaires reaped financial gains and ordinary people struggled as the coronavirus pandemic raged.
“Like a lot of you, I spent a lot of my life with guys like Donald Trump looking down on me, looking down on the people who make a living with their hands,” Mr. Biden said. “People who take care of our kids, clean our streets.”
He added: “These are the guys that always thought they were better than me, better than us, because they had a lot of money. Guys inherit everything they’ve got and still manage to squander it.”
Mr. Biden briefly mentioned the Supreme Court, noting that Mr. Trump was “in the Supreme Court saying, ‘Get rid of pre-existing conditions,’” a reference to a legal challenge to the Affordable Care Act. The Trump administration has asked the court to overturn the law, and oral arguments are scheduled for a week after Election Day.
The speech capped a notably active week for Mr. Biden, who is escalating his travel to battleground states after months in which he mostly stayed in Delaware and held in-person events only occasionally.
This week, Mr. Biden gave two speeches in Delaware, made a trip to Florida and participated in a CNN town hall event near his hometown, Scranton, Pa. He also received a classified intelligence briefing on Wednesday, the first that he has received as the Democratic nominee, a campaign official said.
At the CNN town hall, Mr. Biden described the presidential race as “a campaign between Scranton and Park Avenue,” and he continued to make that case on Friday, saying that the president was “only worried about the stock market and his re-election.”
“All Trump sees from Park Avenue is Wall Street,” he said. “That’s why the only metric of the American prosperity for him is the value of the Dow Jones.”
Mr. Trump said this week, incorrectly, that “stocks are owned by everybody,” and Mr. Biden took aim at him on that subject, invoking Scranton and Claymont, Del., where Mr. Biden’s family moved when he was a child.
“Trump says, by the way, I’m paraphrasing, everyone’s in the stock market,” Mr. Biden said. “That’s why he cares about the stock market. What the hell’s he talking about? People I grew up with in Scranton and Claymont, they don’t have money in stocks. Every penny we made was to pay the bills and take care of the families.”
Mr. Biden assailed Mr. Trump on a number of other subjects, including his handling of the coronavirus pandemic, his reported comments about fallen soldiers, his desire to cut capital gains taxes and his failure to advance an infrastructure plan.
“I know how to do the job of being president,” Mr. Biden said. “No matter how wealthy Donald Trump is, no matter how much he doctors his, if he does, his tax returns, he doesn’t have a clue how to be president.”
At one point, Mr. Biden described the federal budget deficit as “bonkers.” He also laid out a number of his economic proposals, citing his desire for the government to buy American products when it spends taxpayer money, among other things. “I’m not looking to punish anybody,” Mr. Biden said. “But damn it, it’s about time the super wealthy and corporate America start paying their fair share.”