TORONTO -- He’s a man in his 70s known for confusing tangents, garbled speech and awkward speaking blunders that have some observers questioning whether he’s sharp enough to handle the White House.

It’s an attack that Democrats and Republicans alike are using against U.S. President Donald Trump, 74, and former U.S. Vice-President Joe Biden, 77, as both campaigns try to cast their opponent as cognitively unfit for the presidency.

Political strategists say these attacks are risky and likely won’t win over voters — particularly seniors in battleground states like Florida and Arizona, who will play a decisive role in whether or not Trump wins a second term. After all, aging does not inherently lead to cognitive decline, although some studies show that older people can become more susceptible to difficulties with short-term memory loss, word retrieval and multitasking.

Regardless, age is a salient issue this election. Whoever wins on November 3 will become the oldest person ever elected U.S. president, beating a record set by Trump in 2016 when he was 70.

Questions about mental stamina were thrust into the spotlight thanks in large part to Trump attacking Biden — who he’s labelled “Sleepy Joe” — in television interviews and tweets. But Biden has also publicly mused on his opponent’s mental state, framing Trump as a forgetful president who can’t focus long enough to read top-secret briefings.

Last month, Trump told reporters that he took a cognitive test and “aced it.” He later explained in an interview with Fox News’ medical correspondent Dr. Marc Siegel that the test required him to remember five words — person, woman, man, camera, TV — and repeat them back to an interviewer 20 minutes later.

"And you go: 'Person. Woman. Man. Camera. TV,’” Trump said. "And they say 'that's amazing. How did you do that?’"

"I do it because I have, like, a good memory," Trump continued. "Because I'm cognitively there."

Trump has repeatedly challenged Biden to take the same cognitive test so they can compare scores, with Trump suggesting that "something's going on” with Biden.

"You need physical stamina," he said. "You need mental stamina... we have to be sharp... President Xi is sharp. President Putin is sharp. Erdogan is sharp.”

So far Biden hasn’t accepted Trump’s invitation, seen by many as a political trap, but has instead expressed a willingness to compare his cognitive abilities against Trump’s during the fall debates.

Biden has also turned Trump’s line of attack against him, invoking Trump’s own “cognitive capabilities” when it comes to accusations that the president wasn’t paying close attention to important intelligence briefings following reports that a Russian spy agency was offering bounties to Afghan militants to target and kill U.S. soldiers.

"This president talks about cognitive capability. He doesn't seem to be cognitively aware of what's going on," Biden said. "He either reads and/or gets briefed on important issues, and he forgets it, or he doesn't think it's necessary that he need to know it.”

As the candidates question each other’s mental fitness, television and online ads have further drawn attention to the issue.

The Lincoln Project, a political action committee led by George Conway, the notoriously outspoken husband of Trump’s political counsellor Kellyanne Conway, launched an attack ad that stitches together some of Trump’s most embarrassing public moments. Among the highlights are shots of Trump struggling to drink a glass of water with two hands and Trump unsteadily walking down a ramp following a speech at West Point.

Trump later defended his ramp walk in a series of tweets, calling the platform “very slippery.”

A similar ad was launched by the pro-Trump Committee to Defend the President, which suggests that Biden has “lost his mind.”

The ad strings together a series of clips showing Biden — who has struggled with a stutter since childhood — stumbling over his words or making nonsensical claims, such as “I am going to beat Joe Biden.” In another clip on the coronavirus, Biden says: “We have to take care of the cure. That will make the problem worse, no matter what.”

These attack ads might seem off-putting to some viewers, but according to Republican strategist Cory Crowley, they are among the most powerful tools in politics.

“The public will often say they don’t want candidates to go negative, but if you look at polling before and after attack ads, you’ll find you almost always move the needle,” Crowley told CTVNews.ca in a phone interview last month.

However, in this case, Crowley says both candidates attacking each other’s mental fitness is “in all honesty, probably a losing proposition for both of them” because it simply draws attention to a perceived weakness they both share: their ages.

“I think they’re both doing it to even out the score,” he said, noting that Biden may feel pressure to respond to Trump’s personal attacks with a strong show of force.

“If you don’t fire back at everything he says with equal ammunition, I think the fear is that (Biden) will get steamrolled the same way Hillary Clinton did.”

Wayne Petrozzi, a professor emeritus of politics from Ryerson University, says he doesn’t think the candidates’ attacks against each other on age are part of a winning strategy.

"They’re crude and I’m not sure they’ll get a lot of traction with voters,” Petrozzi said. “I don’t believe that the path to re-election victory lies in unleashing a series of that type of ad from now until election day.”

As for Trump’s invitation to Biden to compare cognitive test scores, Petrozzi doesn’t think that will ever happen.

“Biden would be a fool to put himself in a situation where some kind of third party administers cognitive tests to both parties and releases results to both candidates. I think that would be madness. You’re gambling something you don’t need to worry about. You’re reinforcing that point. I cant believe they’ll be that dumb.”

PSYCHIATRISTS RAISE ALARMS

While both candidates’ attacks against each others’ mental faculties peaked this summer, questions about Trump’s cognitive and emotional wellness have been in the public eye for much longer.

Last December, amidst impeachment proceedings, a group of 350 psychiatrists and other mental health practitioners signed a petition delivered to U.S. Congress claiming that Trump’s mental health was rapidly deteriorating and that the president had “the real potential to become ever more dangerous, a threat to the safety of our nation.”

Dr. Bandy Lee, a psychiatrist from Yale University who led the initiative, said the mental decline she has observed in Trump is not related to his age, calling it “beyond normal decline” for someone his age.

“Age does not necessarily bring on decline, it changes thought processes,” Lee told CTVNews.ca in a phone interview. “There are plenty of individual in their 90s and 100s now who are as sharp as they were in their 20s, and so decline is not automatic with age.”

Among the evidence, Lee cites Trump’s public appearances that she says show frequent and worsening memory lapses, repetitive speech, diminishing vocabulary over time, and an inability to sustain a train of thought.

“So we have a lot of footage on him, videos going back decades, and observing him over time, there has been a difference that could not be attributed to normal aging,” she said.

However, Lee says she is not concerned by those behaviours. What troubled her to speak out as a medical professional, she said, was Trump’s “tremendously fragile sense of self” that she fears could enter into “narcissistic rage” if his “grandiose self image” is not met.

“His inability to tolerate reality, as a result, makes him resort to fantasy thinking that has had catastrophic consequence in terms of the pubic health emergency that we’re experiencing,” Lee said, referring to the COVID-19 pandemic.

While Lee has expressed concerns and suggested that Trump’s behaviour is linked to “some sort of pathological process,” she hasn’t gone so far as to offer a specific diagnosis.

“The exact diagnosis would not be possible without his full medical records, and I don’t diagnose from a distance. But when there is danger to public health and safety, then we have a professional societal duty to warn the public,” she said.

“And that’s why I’ve been speaking out about Donald Trump and not about Joe Biden, because in my view he does not rise to that threshold.”

Dr. John Zinner, a psychiatrist and clinical professor at the George Washington University School of Medicine who also signed the petition, said he believes Trump has narcissistic personality disorder, a condition characterized by a lack of empathy, troubled personal relationships and an inflated sense of self-importance.

“The heart of it is his failure to have an internal sense of worth,” Zinner said, pointing to Trump’s favourite insults against others as examples of projection.

“So when you hear him talk about someone be a loser or a crook or a liar or weak, all of those are projections of the way he feels about himself internally,” he said. “He gets rid of those terrible feelings about himself by locating them in others.”

Neither Zinner nor Lee expressed concerns about Biden’s mental capabilities.

“No, it’s a false equivalence to say it’s in any way alike,” Zinner said.

Some within the field of psychiatry have criticized those who signed the petition, calling it unprofessional for medical professionals to speculate on the president’s mental abilities. However, Lee said she felt obligated to say something.

“I really do think it is central that mental experts give input on this topic,” she said.