Joe Biden is pulling out all the stops to prove his competency – but will it work?

In the two weeks since that disastrous debate performance, Joe Biden has been busy.

He spent the first few days visiting donors, trying to reassure his financiers that he was up to the job. Then – more than a week later – he kicked off his public reconciliation tour, holding a series of interviews as he seeks to convince Americans that his halting 27 June debate appearance was just a bad night.

So far, the results have been mixed. In a 22-minute interview with ABC on 6 July, Biden attempted to pass off the debate, where he at times struggled to complete his thoughts and stumbled over words, as the result of both a cold and a busy travel schedule.

But while his tone was defiant – Biden said only “the Lord almighty” could persuade him to leave the race – some of his answers were still meandering. A couple of interviews with local radio stations in swing states in the following days largely went unnoticed, until a Philadelphia radio host was fired for asking Biden questions that had been submitted by his campaign team.

Related: The Democrats who have called on Joe Biden to step down

All in all, it hasn’t quite been a roaring return to form.

“The real challenge for him will be that it’s awfully hard to prove, as an 81-year-old man, that somehow you’re not an 81-year-old man,” said Marjorie Hershey, professor emeritus of political science at Indiana University Bloomington.

“The slightest deviation from immense competence will be perceived as fatal to him.”

That was evident in a telephone interview with the left-leaning MSNBC news channel on Monday, when Biden fiercely criticized Democrats who wanted him to drop out. The White House was later forced to deny that he was speaking from notes, after people noticed the sound of apparent paper shuffling during the interview.

Undeterred, Biden plans to sit down with NBC on Monday for an in-person prime-time interview, and Hershey said it was difficult to see whether Biden’s strategy should change.

“Voters who have already made up their minds about Biden will likely be convinced that recent events, no matter how dramatic, simply prove what they already thought about the election,” she said.

“And those who were unsure – and who will probably decide the election result – will likely vote on the basis of how they feel about Donald Trump anyway.”

Away from the media arena, Biden had another chance to prove his credentials during an hourlong Nato press conference on Thursday night. But while he demonstrated his grasp of foreign policy during questions about Ukraine, there will have been groans from his campaign team when Biden, just before the press conference, gave a glowing introduction to “President Putin” as he welcomed Volodymyr Zelenskiy, the president of Ukraine, on to the stage.

Emmitt Riley, a professor of politics and African and African American studies at Sewanee University and the chair of the National Conference of Black Political Scientists, said it was difficult to say how effective Biden’s strategy of being more visible and more open to questions would be.

“I think it’s a little too early to tell. Right now, it appears that the president is trying to do damage control by doing this media tour to convince the American public that he’s still up to the job,” Riley said.

“But when you look at some of the core constituents of the Democratic party, namely Black voters, they’re still in support of Joe Biden. And so time will tell, I think by the end of this week, whether or not Joe Biden has weathered the storm.”

While Biden has undoubtedly been shaky, Riley said there had been a double standard in how the media has covered the president’s weaknesses compared with Donald Trump’s.

“I think that when we contextualize a poor debate performance with the threat that Donald Trump poses to American democracy and the instability of our Nato alliances, of our international coalitions and international institutions, the choice just pales in comparison,” Riley said.

“I think that we would be wise to pivot the conversation back to: if we’re going to ask Joe Biden to leave the race, then we certainly should be asking a person who’s convicted of 34 felonies in a state court to leave the race as well.

“And in addition to that, at a time where convicted felons in the United States are barred from voting in certain states, we now have a convicted felon running for political office and not even being asked to leave the race by mainstream media.”