On Monday night, transparency questions surfaced again as PBS interviewer Charlie Rose grilled former President Bill Clinton about his family's foundation.
In other words, Trump and Clinton have less than two months to close the sale, but most voters aren't sure exactly what they're buying.
Few candidates relish throwing open their most intimate health and financial secrets. But the issue is particularly acute this year given Trump's decades of business dealings. And, of course, Trump, 70, and Clinton, 68, would be the oldest and second oldest presidents inaugurated for a first term in a job that comes with intense physical and mental demands -- making their health a highly relevant issue.
When asked by CNN's Anderson Cooper Monday
why she kept her pneumonia diagnosis secret, Clinton said she "just didn't think it was going to be that big a deal."
"It's just the kind of thing that if it happens to you and you're a busy active person, you keep moving forward," she said. "I think it's fair to say, Anderson, that people know more about me than almost anyone in public life. They've got 40 years of my tax returns, tens of thousands of emails, a detailed medical letter report, all kinds of personal details."
Trump has said he will soon release details of a physical exam he underwent last week. In an interview Monday with CNN's Wolf Blitzer on "The Situation Room," Republican vice presidential nominee Mike Pence said both candidates should release detailed medical information.
Trump's campaign manager Kellyanne Conway fought back against the allegations Tuesday that Trump's campaign shared Clinton's lack of transparency.
"As far as I can see, there are two major party candidates running for president and only one of them has pneumonia and lied about it, especially to the press because she always treats you all like second class citizens," Conway told CNN's Alisyn Camerota on "New Day."
'People have a right to know'
"People are vying for the highest office in the land," the Indiana governor said. "People have a right to know."
But when it comes to taxes, Pence said Trump wasn't violating any laws by withholding the data, though he acknowledged "there's a bit of a tradition here."
Trump has said he would release his returns once the Internal Revenue Service completes an audit. When pressed why Trump would not release topline information about previous returns now -- which would not interfere with the audit process -- Pence told Blitzer the Republican nominee would release his returns "in totality" and "not parse them out piece by piece."
Still, the Clinton campaign is already trying to use her weekend misfortune to increase pressure on Trump.
"We know more about Hillary Clinton in than any presidential candidate in history ... we know almost nothing about Donald Trump and he has got to come forward," Clinton campaign manager Robby Mook told CNN's Jake Tapper.
Democratic vice presidential nominee Tim Kaine also weighed in.
"I hope that there will be an even standard applied to getting them both to release sufficient information, not just on health but obviously we have the ongoing issue on taxes too," Kaine said in Ohio.
Politicians have long tried to shroud themselves in secrecy to varying degrees.
"You have had candidates that have been a little close to the vest before -- many of them if not all of them having something they would rather not talk about," said Bruce Buchanan, a presidential historian at the University of Texas at Austin.
But this year threatens to set unprecedented levels for the lack of disclosure, Buchanan said, because the election matches up two candidates who have "reputations in that vein."
Presidential candidates have not always been under such a spotlight.
After all, President Franklin Roosevelt took extensive -- and successful -- measures to hide his paralysis during his 1932 election campaign and subsequent presidency. President John Kennedy, despite a conjuring a mythology of youth and vitality, was one of the most unhealthy presidents ever to hold the office -- but his multiple ailments were not common knowledge at the time.
Clinton's case appears to have little in common with those two Democratic presidents -- and pneumonia is a fairly common complaint that should not impair her capacity to serve as President.
But her wobbly exit from a ceremony Sunday commemorating the 15th anniversary of the September 11 attack in New York created a sudden political storm for two reasons.
First, the episode and video of Clinton staggering into her van played into conservative conspiracy theories that she is hiding some kind of secret illness since sustaining a concussion while secretary of state and is not fit to serve -- a narrative without evidence that is often trumpeted by her opponent and his surrogates.
Then, the length of time it took for her campaign to say what is wrong -- with journalists in the dark about where she was -- fostered the idea that something was being covered up.
"It's not health itself that is the problem she has to deal with," CNN senior political analyst David Axelrod said on Monday. "By allowing that six-hour gap they created this sense that they were trying to put one over on people and that is not helpful to her candidacy."
The incident also played out as the Clinton campaign has spent months rebutting arguments against the Clinton Foundation, which Republicans have argued was a conduit for access to Hillary Clinton's State Department. In the Monday interview with Rose, Bill Clinton insisted "we have been as transparent as we can be" when it comes to the foundation.
"We've been more transparent than any other foundation -- more transparent than any other foundation has been asked to be, and certainly more transparent than anybody else in this line of work," he said.
Transparency is often uncomfortable for candidates.
The ultimate public trust
But at the same time, people who run for President are assuming the ultimate public trust -- the Presidency of the United States, a position for which good health and a freedom from conflicts of financial interest are desirable if not essential. So any unwillingness to comply with what have become political norms for disclosure risks reflecting badly on a candidate's character.
Clinton's campaign promised to do better going forward — and is planning to offer more details about her health later this week.
In political terms, she now has little choice.
"If they keep trying to hide and obfuscate her real condition, it is going to be a big albatross all the way to election day," said Douglas Brinkley, a historian at Rice University on CNN's "At This Hour with Berman and Bolduan."
For her part, Clinton's physician did issue a health statement last year certifying that she was fit to serve as President. Trump has offered no such information. His only health disclosure was a note from his doctor saying his health was "astonishingly excellent" and that he would be the healthiest person ever elected president.
Neither candidate has approached the level of disclosure that another senior citizen candidate -- John McCain -- offered in 2008, when the cancer survivor invited select reporters to view over 1,000 pages of health records.
Even if Trump offers more health details, he still risks setting an unprecedented example on financial disclosure for future candidates. The billionaire has steadfastly refused to match Clinton -- and previous presidential nominees -- by releasing years of tax returns.
'Nobody cares about it'
"Nobody cares about it except some of the folks in the media. Nobody cares about it," Trump said in a Fox News interview earlier this month.
Trump has made his record in building a global business a pillar of his argument that he would be able to turn the economy around as President. Yet he has refused to publish tax returns that would allow voters to make their own assessment of his financial health or claims about his income.
Such disclosures would also permit voters and reporters to view Trump's charitable giving, which he has said has been substantial without providing evidence.
Trump did comply with election laws in May requiring candidates to release a financial statement, which claims a net worth of $10 billion and business interests all over the world. Trump also lists 16 liabilities for which he owes at least $315 million, according to the statement.
But the information does not offer details on the source of Trump's annual income -- information that would more typically be available on a tax return. That's important for voters to size up whether Trump would face conflicts of interest as President given his vast businesses interests around the globe. Critics have suggested that Trump could be compromised as President if he has heavy exposure to US adversaries like China and Russia.
It's also possible that Trump's returns show he paid a very low tax rate if his income comes mainly from capital gains or can be written off against property investments -- a factor that could be politically embarrassing.