WASHINGTON (AP) President Joe Biden is on a public and private blitz to shake off concerns about his cognitive capacities.

But with public doubts about his fitness to serve unabating, Bidens every move is now under a withering microscope as any potential stumble risks becoming magnified and delivering another blow to his candidacy.

To wit: As he introduced Ukrainian President Volodymyr Zelenskyy at a NATO summit event Thursday, Biden flubbed and called him President Putin, prompting audible gasps from the audience. He corrected himself, saying, Im so focused on beating Putin before ceding the lectern. Shortly after, at a news conference, Biden errantly referred to Vice President Trump a gaffe that overshadowed what his aides felt was otherwise a commanding performance.

And a significantly hyped interview with ABCs George Stephanopoulos a week earlier was meant to show Biden could handle scrutinizing questions from the media but only flared more concerns from Democrats about whether he could continue to serve as the partys nominee.

If you are going to raise the stakes on one interview, it cant be another example of you being hard to understand not because hes soft, not because hes mumbling, but because his train of thought doesnt make sense, former Obama White House aide Jon Lovett said on his podcast, Pod Save America, this week, referring to the Stephanopoulos interview.

Lovett continued: Everyone is saying, why isnt he out there, why isnt he out there, why isnt he out there? He goes out there, and he offers this middling performance and it ends up being the absolute worst of both worlds.

Still, getting Biden out there in more unscripted settings has been one consistent plea from Democrats who were rattled by his 90-minute debate on June 27 and are seeking assurances that the performance was an unusual blip and not a sign of broader mental decline. They want to see the handshakes, the glad-handling, the lengthy exchanges with journalists that had been characteristic of Biden, particularly during his 36 years in the Senate.

Hes hopscotched from one event to another since: chatting up supporters at a Detroit restaurant ; rallying voters in Wisconsin; stopping at a coffeeshop in Harrisburg, Pennsylvania ; taking some questions from donors, lawmakers and mayors in private virtual calls. Hes hosted Democratic governors at the White House while picking up his pace of news interviews, including with Stephanopoulos, the Houston Chronicle and NBC News, which will air Monday.