Hillary Clinton "lacks the mental and physical stamina to take on" the war against terrorists, Donald Trump said earlier this month.

Isn't that an unusual way for the Republican presidential candidate to attack his opponent's plans for combating the Islamic State and Al-Qaeda? That's the wrong question, because it's not what Trump's comment is about.

In his usual roundabout way, he's really attacking Clinton's health, highlighting a conspiracy theory that has roiled the right-wing corner of the internet ever since Clinton suffered a severe concussion in 2012.

Slowly but surely, insinuations about dementia and other supposed Clinton illnesses have gone mainstream during this election season. Reality-TV doctor Drew Pinsky, talking about Clinton's health in a radio discussion earlier this month, mentioned the possibility of "brain damage" and added: "What is going on with her health care?" And Dr. David Scheiner, President Barack Obama's physician during Obama's years in Chicago, said on CNN this week that the Democratic nominee should undergo a "thorough" neurological examination before Election Day. "We know what happens to football players who have had concussions, how they begin to lose some of their cognitive ability," he said.

(To be fair, Dr. Scheiner also criticized the odd, hyperbolic health report put out last year by Trump's doctor and said Trump is too fat.)

The legitimizing of conspiracy theories has been a hallmark of the Trump candidacy, but the claims about Clinton's health have been particularly pernicious, fueled by fake medical records that have circulated in the blogosphere and a video of Clinton wagging her head in an unusual way while she talks to reporters. ("Wow! Did Hillary Clinton Just Suffer a Seizure on Camera?" a conservative blogger exclaimed, despite the fact that the reporters surrounding Clinton in the video show no concern that anything might be physically amiss with the woman they are all watching closely.)

Trump and his surrogates have been aggressive on this issue. "Go online and put down 'Hillary Clinton illness' and take a look at the videos for yourself," former New York City Mayor Rudy Giuliani has said. OK, let's do that. Here's one:

So there you go. You can decide for yourself the legitimacy of what you saw.

As doctors who have never treated Clinton increasingly go on TV and the radio to express worries about her health, various journalistic efforts have been made in recent weeks to debunk the Hillary health scare. "Basic stories about a candidate's health are almost always political smears, making them a subgenre of the general practice of politics, which abounds with smears," longtime political reporter Jack Shafer wrote in Politico. And CNN put out a long report detailing Clinton's health issues and her opponents' response to them. "There is absolutely no credible evidence to backstop any of these claims, including on the 'videos' Giuliani cited," CNN reported.

Clinton haters and the mainstream media's detractors, of course, dismiss such declarations. Former Alaska Gov. Sarah Palin ended up in the hospital over the weekend after a fall, and in a Facebook post about her own health she launched into a mocking rebuke of Clinton defenders: "Leave Hillary Alone, Bullies," she wrote, adding that anyone questioning Clinton's health is obviously a misogynist. She then returned to her own accident: "Rock-running recently, I tripped over my own two feet and crashed & burned face-first. I recovered with the doc's SuperGlue, and now any man who asks 'what happened?' I'll refer to as just a mean ol' SEXIST bully."

For the record, Clinton's physician, Dr. Lisa Bardack, declared last year that Clinton is "in excellent physical condition and fit to serve as President of the United States."

-- Douglas Perry