The Fix's Aaron Blake explains the incident during which Democratic presidential nominee Hillary Clinton fell ill on Sept. 11, and why her health is likely to remain a subject of discussion. (Peter Stevenson/The Washington Post)

"Trust us."

That's the message from Hillary Clinton's campaign in the wake of a medical incident on Sunday in which the former secretary of state appeared wobbly, at best, as she left a Sept. 11 memorial service early.

Clinton, the Democratic presidential nominee, got overheated and dehydrated at the event because she is battling pneumonia, her doctor said.

"Secretary Clinton has been experiencing a cough related to allergies,” Clinton's doctor, Lisa R. Bardack, said in a statement. “On Friday, during a follow-up evaluation of her prolonged cough, she was diagnosed with pneumonia. 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 re-hydrated and recovering nicely.”

So Clinton was diagnosed with pneumonia Friday. Her campaign said nothing. She almost had to be lifted into her vehicle — if you have not watched the footage above, go back and do it now — because she was struggling to walk the few steps to the car Sunday morning. For 90 minutes, no word of her well-being was released as she recuperated from her "overheating" at the apartment of her daughter, Chelsea. (Clinton did not allow any reporters with her during this time.) Then, hours later, a statement from her doctor says she has been sick with pneumonia for at least 48 hours.

Video of Clinton's departure seemed to show her buckling and stumbling as she got into her van. (Thomas Johnson/The Washington Post)

That's a lot to swallow. That is, of course, not to say it is not accurate. But the Clintons' past history with transparency (not good) when coupled with their response to this incident (also, not good) plays into one of the ongoing narratives of this presidential race: You simply cannot trust Hillary Clinton to tell you the whole truth.

David Axelrod, a longtime Democratic media consultant and close adviser to President Obama, summed up that sentiment nicely in a tweet sent Monday morning:

There is a line that runs through all of Clinton's issues — her private email server, the Clinton Foundation and now her health — in this race. And it is an obsession with secrecy driven by a paranoia of the media.

Think of how differently the email controversy might have turned out if, in that first news conference addressing the existence of a private email server last spring, Clinton would have simply said, "I'm sorry," and told reporters everything she knew about the setup. It's nearly certain that we wouldn't still be talking about it 18 months later.

Why didn't Clinton do that? She's never explained fully. But it's clear that Clinton thought the issue to be a nothing-burger and was convinced that any opening she gave to the media — "I'm sorry, and this is why it happened" — would not solve the problem but only lead to more questions. It's hard to imagine — and, yes, hindsight is 20-20 — that the story could have played out much worse for Clinton than it has.

Study what happened Sunday, and you see a pattern. Clinton is not feeling well. She is taken to Chelsea's house to recuperate. Reporters are in the dark about her health status for 90 minutes. (Before you roll your eyes, consider that she is one of two people with a chance to be president in 56 days.) We are told she has "overheated" by her staff. Then, hours later, it's revealed that, well, actually, she has pneumonia, and it was diagnosed several days ago.

Always a lean toward secrecy and obscuring rather than openness and transparency — amid a bevy of poll numbers that show somewhere between 55 percent and 65 percent of the American public do not believe the words "honest" or "trustworthy" apply to her.

And there is always an emphasis on the need to simply take Clinton's word for it. Trust her that all of the emails that were deleted permanently from her server were purely personal. Trust her that any appearance of pay-to-play with donors to the Clinton Foundation is purely coincidental. Trust her that everything is A-okay with her health after the incident Sunday.

“I know there’s a lot of smoke, and there’s no fire," Clinton told CNN a few weeks back while answering questions about the foundation's donor practices. That appears to be the Clinton line for every controversy that arises in this campaign: We are taking care of it. Everything is fine. Trust us.

But for a candidate that more than half the country thinks is something short of honest and trustworthy, that answer is not likely to be good enough — on Clinton's health or any of the other issues that have come up in this campaign for her.