ARLINGTON, Va. − President Joe Biden's announcement that he will end his re-election campaign quickly swept across the nation Sunday, and Americans grappled with the historic news.

Biden, in a letter to Americans posted on social media, promoted his efforts with the economy, health care, and other issues.

"It has been the greatest honor of my life to serve as your president," Biden wrote. "And while it has been my intention to seek reelection, I believe it is in the best interest of my party and my country for me to stand down and to focus solely on my duties as president for the rest of my term."

Questions about Biden's fitness for a second term as the oldest sitting president have escalated in recent weeks after a disastrous debate performance against former President Donald Trump. Biden, 81, yielded to growing pressure from Democrats to bow out, and he endorsed Vice President Kamala Harris in a separate statement on X.

Nicole McCullough,  41 a licensed professional counselor in Arlington, said she was not surprised. A Democrat, McCullough said Biden's decision was "the right move" for the nation.

"I do think Kamala is an extremely qualified presidential candidate," McCullough, 41, told USA TODAY. "And I think she is ready to lead the American people."

Susan Powers, 72, a Denver resident visiting San Francisco when the news broke, said she was relieved Biden bowed out.

"I feel bad for him as a person, he has done good things for the country, but I think this is the best thing now,'' Powers said. "Personally I’m happy with Kamala Harris as the nominee, though I think they need to quickly find a white man for the vice president’s position.''

Joe Biden drops out of 2024 race:Democrats had pressured him to bow out

'Finally a brave act from a politician'

Peter Reilly, an actuary in Montgomery County, Pennsylvania, said he was "saddened" but said Biden made the correct decision.

"He was always a consummate politician and he correctly understood that this is the best thing for the country," said Reilly, 61. "I hope that in some way it can help mitigate the damage done by him, putting politics above doing the right thing for the country, during his career as a senator. Finally a brave act from a politician."

In Biden's home state of Delaware, retired school teacher and longtime Democrat Judith Gupton Wiley said she just hopes Biden "made this decision because he thought it was the right thing to do, and not that he felt pressured to do it."

Some had no doubt Biden was pushed out, like Jennifer Dhillon of Alameda, California, who runs a nonprofit that focuses on disadvantaged youth.

"I am disgusted and shocked by the party bowing down to the billionaire overlords and disregarding voters who chose Biden,'' she said. "They did him dirty.''

Texas pastor: Biden sincere but wrongheaded

Robert Jeffress, a Trump supporter and senior pastor of the 14,000-member megachurch First Baptist in Dallas, called Biden "a sincere leader who was just wrong about the direction he was leading our nation in.”

Jeffress is an influential Christian evangelical who was among the ceremony speakers when Trump relocated the U.S. Embassy to Jerusalem in 2018. Jeffress said he wished Biden "God’s best in every area of his life and pray for Donald Trump’s success as he becomes our next president."

Who will replace Biden?Kamala Harris is the immediate frontrunner

Focus should be on Trump's 'criminal record, lies'

Vince Virzi, 56, a native San Franciscan, said Americans "deserved a better choice." But he said he would have liked to see more involvement from Harris in the last four years.

"I think it was foolish of them to have her take a back seat," Virzi said. "We could have seen her be more presidential the last year and a half, but let’s see what happens. I liked her as senator and I liked her as attorney general."

John Micheletos, a facilities manager in San Francisco, thought people could line up behind Harris. "I don’t see Biden supporters not supporting Harris, but can she get the voters on the margins? I believe she will get enough of them. Focus on his (Trump's) criminal record, lies, and the fascist Project 2025."

There was no shortage of opinions about Biden's decision in deep-blue San Francisco, including frustration over the Democratic Party's failure to anticipate an 81-year-old president faltering.

“They should have had more foresight,'' said Virginia Plume, 39, a cardiac surgery nurse. "But I’m excited and I hope this stops the erosion of women’s rights in this country.”

GOP activist lauds Biden's decision

In Utah, Republican activist Becky Edwards said she hoped other candidates could learn from Biden's decision. A former member of the Utah legislature, Edwards now runs a political action committee dedicated to supporting Republicans who agree to run positive, constructive campaigns.

"This moment serves as a reminder that the best interests of the people should always take precedence over personal political ambitions," she said. "We hope future candidates will be inspired to focus on unity and productive dialogue." 

'Absolutely endorsing' Kamala Harris, but how about donors?

Alicia Coulter, 46, of Los Angeles, who told USA TODAY last month that she would remain behind the Biden-Harris ticket despite the heavy criticism of the president post-debate, said Sunday that she is firmly behind Harris should she run again for the presidency.

"I'm absolutely endorsing her. I understand the concerns that people think she will not be elected because she's a Black woman, but I know she can do the job as president of the United States," said Coulter, the CEO of a nonprofit that helps organizations with its DEI strategies and create safe spaces for Black women. "Can she lead? Yes, she can.

"Black women are the base of the Democratic party. We will more likely be key surrogates for the new ticket, and if the party jumps over her, it will be hard for us to consider another candidate."  

King Kaufman, a former journalist who now performs as a musician known as the King Teen in Durham, North Carolina, calls Biden’s departure from the race "an avoidable own goal by the Democrats."

"Evidently, the Big Donors don’t want Harris," Kaufman added, pointing to racism as the reason. "But I think the rest of us can unite behind the idea that there would be no better way to send Donald Trump onto the trash heap of history than with a loss to a Black and Indian woman who is the daughter of immigrants and an interracial marriage."

Some expressions of sadness and disappointment

At Mount Vernon, the estate of George Washington just outside the city named after him, Chris Atkinson expressed disappointment that Biden dropped out. "It is something I was hoping wouldn’t happen, but he’s made his decision and we need to support the eventual nominee."

Christine Awad, an artist and art instructor in Mukilteo, Washington, chimed in on social media that she was "hoping he could hang in there!" In a series of short reactions she wrote "sad," and "age and speech disability discrimination."

Two women presidents in North America? Could happen

Sylvia de la Cruz, 66, was traveling to visit an ailing relative in Mexico, where voters recently elected Claudia Sheinbaum as the country’s first woman president, when she got the Biden news. De la Cruz said she would vote for Harris, who she believes "is very well-prepared."

Should Harris earn the Democratic nomination and win the election, there would be two women presidents in North America.

"Is North America ready for that?" she asked. "I think women make very good decisions, and I think we’ve come a long way."

'Great character' but not enough left in the tank

Chicago resident George Velazquez, 60, said he was relieved by Biden’s decision and what it might mean for the issue most important to him − gun violence in the city.

"Maybe he’s fine now but I don’t think he’s got enough left in the tank for another four years," said Velazquez, a veteran gang violence prevention worker. "He’s got a great character. We need someone at the top who is going to advocate for enforcing the laws."

Velazquez declined to say whether he would be supporting Trump or whoever replaced Biden on the ticket.

'We feel like there should be a third option'

Vitaliy Bondarenko, 30, an American citizen born in Ukraine, said Biden "clearly made the right choice" in stepping down."He supports Ukraine but he’s bad for the USA. He can’t remember what he did yesterday," Bondarenko said while on a walk with family through Chicago’s Ukrainian Village on Sunday.But he doesn’t like Harris and, though he tends to prefer Trump, wasn’t sure he could trust the former president to secure peace in his native country without ceding too much territory to Russian President Vladimir Putin."We feel like there should be a third option," he said. "Whoever would support Ukraine, we would support."

Conservative on Dems: 'Americans are suffering from their leadership'

Cole Marting, a California conservative, criticized the Democratic Party after Biden announced his withdrawal earlier Sunday.

In a statement to USA TODAY, Marting, a member of the San Diego Young Republicans, called Biden’s withdrawal a "clear sign that the Democratic Party has failed to address the critical issues of our generation," adding: "Regardless of the name at the top of the Democrat ticket, Americans are suffering from their leadership."

Contributing: Megan Smith, Terry Collins, Elizabeth Weise, Lauren Villagran, Michael Loria, Marc Ramirez, and Thao Nguyen