Biden stumbles over his words as he tries to kick-start his re-election campaign

President Biden tried to steady his reelection campaign by speaking to two black radio hosts for interviews that aired on Thursday, but he faltered at points during one interview and struggled to find the right line in the other. He said he was proud to be “the first black woman to serve with a black president.”

He also stumbled over his words during a four-minute speech to military families at the White House on July 4, launching into a story about former President Donald J. Trump, calling him “one of our colleagues, the former president” and then adding, “I probably shouldn’t say that anyway,” before abruptly ending the story and moving on.

Mr. Biden made the mistake on WURD radio, based in Philadelphia, when he tried to deliver a line he had repeated earlier about being proud to be vice president for President Barack Obama. Earlier in the interview, he had bragged about appointing the first black woman to the Supreme Court and choosing the first black woman as vice president.

The president also made a mistake earlier in the interview when he claimed he was the first president elected at the state level in Delaware. He seemed to mean he was the first Catholic elected at the state level in the state, and then he spoke admiringly of John F. Kennedy, a Catholic.

Biden and his top advisers have said the president’s activities in the coming days are part of a series of campaign efforts designed to prove to voters, donors and activists that the president’s debate debacle was nothing more than what he called “a bad night.”

The president’s every performance has come under intense criticism since he appeared listless and distracted during Thursday’s debate with former President Donald J. Trump, a performance that sparked concern among Democrats about whether he is too old to remain the party’s nominee.

The president will interview ABC’s George Stephanopoulos on Friday after a campaign rally in Madison, Wisconsin. He will appear at a campaign rally in Philadelphia on Sunday.

On Thursday, the president attempted to assuage concerns about the debate among members of the black community through radio interviews.

In Mr. Biden’s appearance on “The Earl Ingram Show,” which is aimed at black listeners in Wisconsin but also airs nationwide, Mr. Ingram opened his show by asking the president to “talk about some of the accomplishments that we may or may not know about your record.”

But despite the low-key nature of the interview, the president’s speech sometimes faltered as he delivered his rapid-fire answers. Asked why voting mattered, Mr. Biden offered an answer about the Supreme Court’s ruling this week granting immunity to Mr. Trump.

“You need someone, someone who is going to make sure that — the Supreme Court just made a decision, by the way, that threatens the American principle that we have no kings in America,” he said. “No one is above the law.”

“That’s where we always — we gave Donald Trump executive authority to operate a system — and it was just never considered by our founders because of the people that he appointed to the court,” he said, appearing to stutter several times, a condition he’s struggled with since he was a child. “It’s just presidential immunity. He can say I did this in my executive capacity, it may have been wrong, but I did it. But that holds up — because I — and this is the same guy who says he wants revenge.”

The president’s answers to Mr. Ingram’s four questions were lengthy, as he largely confined himself to listing his accomplishments in office and criticizing Mr. Trump. But during the 17-minute interview, he occasionally stopped in mid-answer.

In the answer about the importance of voting, he started talking about Mr. Trump’s proposal to increase tariffs on all Chinese goods imported into the United States. He stopped himself mid-answer and apologized for going on too long.

“He wants a 10 percent tariff on everything imported into the United States,” he said, “which will increase taxes for the average American by $2,500, while the next time he gives a $5 trillion tax cut for everyone who earns — either way, I don’t really want to get too caught up in it.”

Mr. Biden also refrained from using an expletive to describe Mr. Trump during a response in which he referred to his son Beau, who died of brain cancer after serving a year in Iraq. Mr. Biden has blamed his death on his proximity to so-called burn pits, where waste was dumped.

“He went in a very healthy man, came back with stage 4 glioblastoma — more brain damage in that war than in any other war — and he died,” Mr. Biden said. “I’ll be damned if I’m going to let this SO — excuse me — this president talk about veterans the way he talked about veterans.”

At the end of the interview with Mr. Ingram, the President again acknowledged his poor performance during the debate.

“The fact is, you know, it was — I messed up,” he said. “I made a mistake.”