President Biden’s withdrawal from his reelection campaign Sunday ended weeks of speculation about his political future. But continued questions about his health have given rise to a new question: Should he resign from the White House, too?

The 81-year-old president wrote on social media that he would “focus all my energies on my duties as President for the remainder of my term.” There are about six months – 183 days – until Biden’s term would end.

The White House has reiterated for weeks that Biden’s high-profile debate flop was an outlier and that the president remains fit to serve. But administration officials, lawmakers from both parties and Democratic donors have raised questions about the president’s cognitive fitness, pointing to alarming moments in private in which Biden seemed distant or confused, and his repeated flubs in public.

Republicans on Sunday demanded that Biden step down.

“If Joe Biden is not fit to run for President, he is not fit to serve as President,” House Speaker Mike Johnson (R-La.) said in a statement. “He must resign the office immediately.”

Democratic leaders generally don’t share that view. Lawmakers showered Biden with appreciation Sunday, and several said they remain confident in his leadership as president. Biden, who is recovering from a bout of covid, had repeatedly said he was up to the job of both running the country and campaigning for reelection.

“I’m good,” Biden said during a July 11 news conference following the NATO summit, adding that age “creates a little bit of wisdom if you pay attention.”

Andrew Bates, a White House spokesman, said Sunday that Biden would continue to focus on priorities such as creating jobs and fighting abortion bans for the rest of his term. “He looks forward to finishing his term and delivering more historic results for the American people,” Bates wrote in an email.

Some Democratic officials and allies have privately argued that Biden stepping down from the presidency – and immediately elevating Vice President Harris into the Oval Office – would confer additional political benefits in a challenge against Donald Trump.

Outside medical and policy experts said that the job of campaigning – which required Biden to energize voters, engage with donors and give stump speeches around the country – calls on a different set of physical and cognitive skills than serving as president, where Biden is presented with decisions and surrounded by advisers. Biden, some say, is equipped to serve out his term.

“The presidency is not a one-man show,” said Ezekiel Emanuel, a University of Pennsylvania bioethicist who advised the Biden administration on its covid response and other health issues. “It is an administration with the president as boss and ultimate decision-maker … and he has a very effective team around him that he knows, and they know him.”

David Grabowski, a Harvard Medical School professor who specializes in the study of aging, emphasized the distinction between Biden’s ability to finish out the remaining months of his presidency vs. his capacity to do so for another term as an octogenarian.

“President Biden’s decision to end his candidacy relates to carrying out his duties over the next four and [a] half years,” Grabowski wrote in an email. “From an aging and health perspective, that is different from his fitness to serve today through the end of his current term. The two must be evaluated independently.”

Some of Biden’s aides and allies had insisted – as recently as Sunday morning – that he would not drop out of the 2024 presidential race. But the shifting political reality had complicated his reelection bid: The president had been lagging behind Trump in polls across key battleground states, even as other Democrats fared better in hypothetical matchups against Trump.

While the 78-year-old Trump has had his own struggles – such as confusing names, misstating facts and delivering often meandering speeches – voters have generally expressed more concern about Biden’s age than Trump’s. A CBS News/YouGov poll conducted last month found that 72 percent of registered voters believed Biden lacked the mental and cognitive health to serve as president, compared with 49 percent who felt the same of Trump.

Biden was last examined by a team of medical specialists earlier this year, according to a summary released in February by Kevin O’Connor, Biden’s longtime physician. The physicians concluded that Biden was “a healthy, active, robust 81-year-old male, who remains fit to successfully execute the duties of the Presidency,” O’Connor wrote.

The specialists ruled out neurological disorders such as stroke and Parkinson’s, although they noted that Biden had developed an increasingly stiff gait and appeared to suffer from peripheral neuropathy – a type of weakness or nerve damage – in both of his feet. Kevin Cannard, a neurologist who specializes in movement disorders such as Parkinson’s, was among the physicians who examined Biden as part of that review.

Biden’s performance in his June 27 debate against Trump – during which the president struggled to explain some of his core policies and repeatedly tripped over his words – prompted worries from Democrats but also health experts who feared a deeper medical problem. Three former members of the White House medical unit who had previously cared for Biden told The Washington Post that they believed the president should undergo cognitive screening, given his rocky debate performance.

Biden had repeatedly declined to seek a cognitive test, telling reporters that he is “tested every single day” on his fitness by the duties of the presidency, but he showed signs of relaxing his position at the July 11 news conference.

“I am not opposed,” Biden said at the news conference. “If my doctors tell me they should – I should have another neurological exam, I’ll do it.”

Biden’s physical and verbal stumbles have worried lawmakers, administration staff and high-level donors who have privately interacted with him in recent months. They said he has become more visibly frail, sometimes in need of physical assistance as he takes the stairs or moves around a room. The lifelong politician known for uncorking long, freewheeling speeches has become increasingly difficult to hear and understand.

Biden has occasionally appeared to briefly freeze up or suddenly veer off topic, instances some said they easily dismissed before the debate but that have caused them to question his ability to do the job for another four years.

The campaign trail exposed these weaknesses. Donors in recent weeks – including actor George Clooney – have said Biden seemed feeble, tired or confused in their small sessions, fueling calls for him to withdraw his reelection bid.

One Democratic donor, who met with Biden in small meetings at the White House early in his presidency and spoke on the condition of anonymity to candidly discuss the president’s fitness to serve, recalled an encounter with Biden at a fundraiser this year.

“He was different than I’d experienced him in the White House,” the donor said, adding that Biden’s affect in a private meeting at the fundraiser was similar to his performance in the debate. The president was “quieter,” with his remarks trailing off, and engaged in some “staring into space.”

“He felt like an elderly person,” the donor said.

White House aides who work with the president regularly and accompany him on foreign trips said that while Biden may move slower and look older, they do not see signs he is mentally diminished and say his physical aging has no bearing on his ability to continue the job of president.

“I think two things can be true – that he’s fully capable of finishing this term as president but it’s not realistic to expect him to vigorously serve another four years,” said Jonathan Reiner, a cardiologist and professor of medicine and surgery at the George Washington School of Medicine and Health Sciences. “I do think it would be appropriate for a formal statement from the White House medical team attesting to presidential capacity.”