From the Washington Post’s aptly named column “The Fix” last Tuesday

By Chris Cillizza September 6

… Led by Drudge, there have been questions circulating in the conservative media — and among Trump surrogates like Rudy Giuliani — that “something” is wrong with Clinton for months. Much of that speculation ties back to an episode in late 2012 in which Clinton caught a stomach virus, fell, suffered a concussion and was then hospitalized due to a blood clot. A certain sector of conservatives were convinced that more was going on with her health than ever became public and that this was yet another example of the Clintons hiding things from the public.

“Diagnoses” have run everywhere from a severe thyroid problem to traumatic brain injury to dysphasia. (That last one comes courtesy of Trump national spokeswoman Katrina Pierson, who, in case you were wondering, is not a doctor.)

And, of course, Trump sounded off on the whole thing Tuesday via Twitter.

Mainstream media never covered Hillary’s massive “hacking”

or coughing attack, yet it is #1 trending. What’s up? — Donald J. Trump (@realDonaldTrump) September 6, 2016

Here’s the thing: This is a totally ridiculous issue — for lots of reasons — and one that if Trump or his Republican surrogates continue to focus on is a surefire loser in the fall. …

So, to believe that something is seriously wrong with Clinton, you have to a) assume her doctor lied and b) that her coughing, which often happens when someone catches a cold or spends a lot of time speaking publicly, is a symptom of her deeper, hidden illness.

That seems, um, unlikely to me? Beyond the Clinton conspiracy theorists who believe she had something to do with Vince Foster’s death and that she was secretly responsible for everything from Y2K to the SpaceX explosion last week, it’s hard to plausibly insist, based on the available data, that Clinton is ill. There’s the doctor’s note, plus she keeps a very rigorous schedule for a 68-year-old — traveling all over the country to raise money and campaign. (For the past month, she’s done a lot more raising money than campaigning.) …

The simple fact is that there is zero evidence that anything is seriously wrong with Clinton. If suffering an occasional coughing fit is evidence of a major health problem, then 75 percent of the country must have that mystery illness. And I am one of them.

What Trump cannot — or, at least, should not — do is continue to engage with these wacky theories that emerge out of the fever swamps on the very fringe of the conservative movement. Every single person who believes in the Clinton health conspiracy is already for Trump. What he needs to do is find ways to reach voters who have doubts about him but may carry even graver doubts about Clinton’s ability to do the job in an honest and transparent way.

Clinton’s botched handling of her private email server, the questions raised by the Clinton Foundation’s foreign donors — these are ripe issues for Trump to make a case against Clinton. Every second he or his surrogates spend talking about Clinton’s health is a lost moment for his campaign. And with 63 days left until the election, he simply can’t afford that.

Chris Cillizza writes “The Fix,” a politics blog for the Washington Post. He also covers the White House. Follow @thefix