Kirsten Powers

It was the stumble seen around the world.

A video showing Hillary Clinton wobbling, then legs buckling, as she was held up by a Secret Service agent Sunday breathed new life into conspiracy theories surrounding her health.

Donald Trump and his surrogates have feverishly pushed claims that Clinton “lacks physical stamina,” “looks sick,” “takes naps,” and according to Trump spokesperson Katrina Pierson, suffers from “dysphasia,” a speech disorder sometimes caused by brain disease or damage.

These accusations were made in the absence of any actual incident involving Clinton’s health. Then, her critics latched onto a Labor Day coughing fit, which lasted approximately two minutes, as proof that Clinton was enfeebled by a mystery illness. Imagine their glee upon seeing a video of Clinton struggling to maintain balance, an incident her doctor has attributed to pneumonia and dehydration.

Other leaders have not just stumbled but have fainted outright. They include President George H.W. Bush, who vomited and then fainted at a state dinner; his son George W. Bush, who passed out after choking on a pretzel; and then-Gen. David Petraeus, who fainted at a congressional hearing. The elder Bush went on to maintain such excellent health that he was skydiving at age 90. His son has also been the picture of health. Petraeus’ public face-plant, which was chalked up to dehydration, didn’t cause anyone to deem him unfit to lead. He was later appointed CIA director.

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But I’m being too rational. This is what Dilbert creator Scott Adams, who has been blogging about the election, explained to me in an interview. He predicted in October that Trump would prevail in the primary due to Trump's mastery of persuasion, something Adams has studied for decades. Adams also predicted in December that we'd learn of an important Clinton health issue before the general election. Adams said he doesn’t consider policies or personal preferences in making his predictions. He focuses on the impressions the candidates make.

“If you look at the health claims against Clinton one by one, they don’t mean anything,” Adams told me. “Clinton’s coughing wouldn’t mean anything if (her health) hadn’t already been raised. You have to understand that people don’t use rational thought to make decisions. We rationalize after we make a decision. It’s all about making accusations and associating people with bad feelings.”

Trump raising Clinton’s health is an example of what Adams calls “linguistic kill shots.” We’ve seen how effective these can be. Just ask “Lil' Marco” or “Low Energy Jeb.”

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“If you were trying to design the worst luck a candidate would ever have, it would be one already being dogged with health questions running to be commander in chief who has an episode on the site of the worst case of terrorism in our living memory,” Adams noted. “To be there at that time and that location … and literally have your knees buckle … forget about data, logic, facts. The visual is so strong. Seeing her buckle in association with 9/11 imagery makes it almost impossible for her to win.”

Perhaps a bigger problem for Clinton is that this incident feeds into the primary narrative about her: that she isn’t trustworthy and lacks transparency. She — like Trump — has yet to release her medical records, as both John McCain and Mitt Romney did. Moreover, her campaign took an hour-and-a-half to provide any information about her collapse. When they did speak, it was to offer shifting explanations, with the first iteration of the story including no mention of her pneumonia. This doesn’t exactly breed trust.

Had she not been captured on camera stumbling to her car, we likely never would have known she had suffered pneumonia. Which brings us to an obvious question for Hillary Clinton: Is there anything else we need to know?

Kirsten Powers, a CNN political analyst, is a member of USA TODAY’s Board of Contributors. Follow her on Twitter: @KirstenPowers

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