IT WAS a small stumble by a sick and tired 68-year-old woman. Yet the dizzy spell Hillary Clinton suffered on September 11th, which caused her to retreat, tottering, from a memorial service in New York, looks like a giant gift to Donald Trump. A video clip, circulated feverishly on Twitter, showed Mrs Clinton appearing to collapse momentarily into the arms of her bodyguards as she was forced to leave the service for the victims of the 9/11 attacks prematurely. She proceeded to the nearby home of her daughter, Chelsea, to recuperate.

“Secretary Clinton attended the September 11th commemoration ceremony for just an hour and thirty minutes this morning to pay her respect and greet some of the families of the fallen,” said a spokesman for the Democratic nominee. “During the ceremony, she felt overheated, so departed to go to her daughter’s apartment and is feeling much better.”

Re-emerging to public view, 90 minutes after her enforced exit, Mrs Clinton did appear to be recovered. “I’m feeling great,” she told a small crowd of onlookers. “It’s a beautiful day in New York”. But the extent to which that was crisis management was made plain in a subsequent statement from her doctor—which revealed that the former secretary of state has pneumonia.

“Secretary Clinton has been experiencing a cough related to allergies. On Friday, during follow-up evaluation of her prolonged cough, she was diagnosed with pneumonia,” said Dr Lisa Bardack, after examining Mrs Clinton later on September 11th. “She was put on antibiotics and advised to rest and modify her schedule. While at this morning’s event, she became overheated and dehydrated. I have just examined her and she is now rehydrated and recovering nicely.”

This was uncharacteristic candour from the disclosure-averse Mrs Clinton, indicating the potential calamitousness of her stumble. It comes at a perilous time for her campaign, with recent polls suggesting her once-ample lead over Mr Trump has shrivelled to around three percentage points—almost within the margin for error.

Making matters worse, conspiracy theories have long circulated among her enemies on the right about the supposedly poor state of her health, triggered by an episode in 2012 in which she fainted, suffered a concussion, and was subsequently found to have a blood clot. Mrs Clinton has since been given a clean bill of health by her doctors. Yet Mr Trump and his supporters have laboured to suggest she is weak and unwell.

In a speech in April Mr Trump insinuated that, as secretary of state, Mrs Clinton had failed to protect the four Americans killed by Jihadists in Benghazi in 2012 because she lacked the physical vigour necessary to deal with a night-time emergency. “Instead of taking charge that night, Hillary Clinton decided to go home and sleep. Incredible,” he said.

Like so much of Trump utterance, this was nonsense. The attacks in Benghazi took place in daytime in America, and Mrs Clinton, multiple official investigations suggest, oversaw a creditable official American response to them. Yet the official verdict is not widely believed. Indeed, given that almost half of Republican voters claim to think that “as secretary of state, Hillary Clinton knew the US embassy in Benghazi was going to be attacked and did nothing to protect it,” her alleged ill health is the least of their poor view of her.

Mrs Clinton’s habits of secrecy and, when challenged, obfuscation, have also played into her accusers’ hands. To explain her misleading claim to have been entirely vindicated by an FBI investigation into her singular email arrangements in the State Department, Mrs Clinton claimed to have momentarily “short-circuited”. Mr Trump naturally ran with that. “She took a short-circuit in the brain. She’s got problems,” he said. “Honestly, I don’t think she’s all there.”

The Republican nominee’s attack dogs have gone further. Rudy Giuliani, a former mayor of New York, who was once forced by ill health to cancel plans to run against Mrs Clinton for the Senate, and who appears to hate her, has accused her of looking “tired” and “sick”. Katrina Pierson, a Trump spokeswoman, claimed, on the basis of no evidence, that Mrs Clinton has dysphasia, a form of brain damage.

The reality is that Americans really should be a bit concerned about the health of their next president—whoever wins in November. Mrs Clinton would be the second oldest new president after Ronald Reagan, who is thought to have been showing signs of the dementia that would haunt his last years by the time he ended his presidency, aged almost 78. Mr Trump, who is two years older than Mrs Clinton, would be the oldest new president—and, despite his haranguing of Mrs Clinton, he, typically, has broadcast a much thinner medical record than she has.

Mr Trump’s disclosure consists mainly of a statement, produced last December, by a gastroenterologist, Dr Harold Bornstein, which described his blood pressure and other indicators as “astonishingly excellent.” Dr Bornstein was pleased to conclude that: “If elected, Mr Trump, I can state unequivocally, will be the healthiest person ever elected to the presidency.” This, Dr Bornstein has since admitted, was not a terribly serious appraisal. When it was put to him that it sounded very much as if it had been written by his patient, Mr Trump’s doctor suggested he had, “probably picked up his kind of language and then just interpreted it to my own.” No matter. Mr Trump’s health is not an election issue and Mrs Clinton’s, now more than ever, is.

Provided she is truly suffering nothing worse than her doctor has indicated, and that she recovers swiftly, her bad turn could end up doing her no serious harm. Though never widely adored, Mrs Clinton has tended to thrive in adversity—as in the humiliating aftermath of the Monica Lewinsky revelations, when her approval rating touched 66%, and towards the end of her gruelling defeat by Barack Obama in the 2008 Democratic primaries, when she was said to have relaxed and improved her performance on the stump.

Now beset by plunging polls and abysmal trust ratings, she urgently needs more of that positive press. Perhaps the notion of her battling on bravely despite feeling ghastly—as is sometimes said to be a woman’s wont—will help with that. But this may be a slender hope.

Mrs Clinton’s ill health has made her look weak. That is an impression that could prove especially damaging for a woman: sexism is plainly behind some of the titanic hatred of Mrs Clinton. Her campaign’s repeated, and patently untrue, denial that there was anything seriously wrong with her—even, for several hours, after her painful exit from the 9/11 service—has probably also reinforced its reputation for shiftiness.

Perhaps most seriously, for Mrs Clinton and the world, her affliction might seem to have vindicated Mr Trump and his fellow conspirators. The truth, of course, is that pneumonia is not dysphasia. Yet millions of Americans, livid with Mrs Clinton and the establishment politics she represents, might just consider that to be splitting hairs.