The outrage was swift and resolute: Karl Rove had delivered a blow beyond the pale when he suggested – insinuated, hinted, alluded to, without actually saying it – that an aging Hillary Clinton might have brain damage.

“Thirty days in the hospital?” Rove said during a conference in Los Angeles in May. “And when she reappears, she’s wearing glasses that are only for people who have traumatic brain injury? We need to know what’s up with that.”

Rove was referring to the concussion suffered by Clinton in December 2012, when she was coming to the end of her tenure as secretary of state. Doctors later discovered that she had a blood clot in the vein that runs between her skull and brain behind her right ear. She spent three days at New York Presbyterian Hospital, not 30, as Rove said.

That error, plus Rove’s reputation as a ruthless political operative, brought widespread criticism. Clinton soon after her illness stepped down from her post (President Barack Obama appointed Sen. John Kerry). But at 66, she has been making the rounds at speaking engagements, and on Tuesday her book “Hard Choices” will be published. This has fueled speculation for months that she will run for president in 2016, and if she does, she’ll be the front-runner for the Democratic nomination.

Republicans may be well-advised to raise questions about her fitness for office, even at this early stage, when no major candidate has yet officially declared him- or herself a candidate. And Americans seem to be of the opinion that her health and age shouldn’t be an issue. A Washington Post-ABC News poll last week showed that two-thirds of respondents disapproved of the issues Rove raised.

Are those questions, which overnight went from whispers to screams echoing in the 24-hour cable-news landscape, simply dirty politics? Or are they part of a larger debate about the physical and mental abilities presidents and candidates should exhibit?

This is not an academic exercise, since throughout American history, there have been many examples of crucial health information about sitting presidents that was deliberately kept from the public.

Dr. Michael Brant-Zawadzki, executive medical director at the Hoag Neurosciences Institute in Newport Beach, says there have been raging debates in the medical community about whether older doctors should be tested to see whether their cognitive abilities have waned.
Many CEOs of big companies are scrutinized in such a way as well. So why not the leader of the free world?

“The population has a stake in making sure that people responsible for their lives are not impaired,” he said.

A certain amount of memory loss as we age is normal. But it would be important to know the moment when a person begins a real cognitive decline that might lead to dementia or Alzheimer’s disease. Obamacare now requires Medicare to pay for a cognitive test for people 65 and older during their annual wellness visit. The goal is to get dementia patients treatment as soon after diagnosis as possible.

There’s no way to tell whether Clinton’s concussion – caused by a fall – precipitated her blood clot, or the clot caused her to lose consciousness and fall. She seems to have made a full recovery, and the effects of the clot likely are not permanent. But Clinton, who had a blood clot in her leg (called a deep vein thrombosis) as first lady in 1998, might have a genetic predisposition to “sludgy” blood, which could make clots more likely than among the general population.

“It didn’t seem to be a permanent event of any sort,” Brant-Zawadzki said. “But we don’t know, and her doctors probably don’t even know, because I doubt they tested her cognitive status before and after, and for most normal functions, to you and me, to the untrained eye, or to the untested individual, you wouldn’t be able to tell. And so that may be good enough for any typical life activities, or even leading the country.”

Every move Clinton, or Jeb Bush, or any other potential candidate for president makes between now and 2016 will be closely scrutinized. “You can’t hide,” said Lori Cox Han, a professor of political science at Chapman University. “As president or a presidential candidate, you’re on stage constantly.”

If Clinton were elected as the nation’s first female president, she would be 69 and 86 days on Inauguration Day 2017, the second-oldest president in the nation’s history at that point; Ronald Reagan was 69 and 348 days on Inauguration Day 1981.

Han dismisses speculation that Clinton’s gender has made her a more available target than a man would be in a similar situation.

“There is absolutely no gender bias,” she said. “This is a completely legitimate question we’ve asked of presidential candidates for years.”

Brant-Zawadzki says one issue that gets overlooked is that older people have an advantage over their juniors in at least one area: wisdom.

“Even though our processing speed and some memory wanes with age, what has been found is that wisdom actually increases with age,” he said. “So there’s a good reason to think about our leaders as being preferable if they have some age under their belts, right? Neuroscience points to, ‘Hey, it’s better to consider older folks for leadership positions, because wisdom accrues with age.’”