The 2016 political campaign, heretofore marked by concerns over Republican Donald Trump's temperament and knowledge to be president, has suddenly pivoted to whether Hillary Clinton's health is up to the same challenge.
Her forced interruption to her campaign over the weekend dramatically focused attention on a question that Mr. Trump had sought to make a central issue: whether Ms. Clinton lacks the stamina for the job.
In purely political terms, her failure to disclose that her doctor had diagnosed her with what is called walking pneumonia only underscored her penchant for personal secrecy, which has long plagued her political career.
Aides sought to defend that failure as evidence of Ms. Clinton's gritty determination to "power through" the immediate difficulty and continue her strenuous schedule, despite medical advice to take a few days off the trail to recuperate.
But by keeping her traveling press companions in the dark for several hours about her whereabouts and condition -- and accordingly the American people -- her campaign compounded the negative public perception of the woman's cloak of privacy, sheltering an unavoidably public life.
David Axelrod, President Obama's former White House political strategist, offered pointedly: "Antibiotics can take care of pneumonia. What's the cure for an unhealthy penchant for privacy that repeatedly creates unnecessary problems?"
Also unavoidably, the development has increased pressure on Mr. Trump, at age 70, two years older than his opponent, to release more information about his own physical health and medical records. Ms. Clinton's call for Mr. Trump to release his recent tax returns as well have had little value.
During her continued campaign, she committed a damaging gaffe in sarcastically labeling half of Mr. Trump's supporters as "a basket of deplorables": "racist, sexist, homophobic, xenophobic, Islamophobic -- you name it."
To attuned political ears, it was a reminder of Mitt Romney's 2012 dismissal of "47 percent of Americans" on federal welfare who would never vote for him.
Mr. Trump's campaign predictably pounced on Ms. Clinton's remark, and the Clinton campaign was obliged to undertake damage control for a candidate previously regarded as a cautious expert in political self-preservation.
Prior to her stumbling departure from the 9/11 memorial service, Ms. Clinton was scheduled to embark on a California schedule of fund-raisers and public events. Instead, she was obliged to break off to recuperate, with husband Bill Clinton filling in for her.
Her resumption of campaigning inevitably will be under sharper scrutiny now, and speculation about her health will continue. Attention will continue to focus on Clinton's politically unwise dig at Mr. Trump's broad base of supporters rather than on Trump's qualifications for the presidency, as she might have hoped.
Beyond the immediate ramifications of Hillary Clinton's oratorical gaffe is the imperative that both nominees come clean in detail about the state of their health and their abilities to serve the next four years in the Oval Office.
The most regrettable history of illness in the White House was the shielded incapacity from 1919 into 1921 of President Woodrow Wilson, after a massive stroke that paralyzed his left side. His wife Edith forbade disclosure of the seriousness of his condition to the point that even Vice President Thomas Marshall was not informed and was barred from his sick room.
Finally informed of the facts by a White House reporter, J. Fred Essary of the Baltimore Sun, Marshall vowed he would do nothing to intervene. He told his secretary: "I am not going to seize the place and then have Wilson, recovered, come around and say, 'Get off, you usurper!' " He told his own wife: "I could throw this country into civil war, but I won't." Wilson, still infirm, served out his second term.
In 1955 President Dwight Eisenhower suffered a heart attack and in 1957 a mild stroke. Vice President Richard Nixon was immediately notified, and Ike signed a draft letter of resignation in the event he were to become disabled, stating Nixon would become acting president pending Eisenhower's recovery.
In the present circumstance, the voters have the right to know now whether the two nominees are fit to serve, and each should be fully forthcoming in the matter.
Jules Witcover is a syndicated columnist and former long-time writer for The Baltimore Sun. His latest book is "The American Vice Presidency: From Irrelevance to Power" (Smithsonian Books). His email is email@example.com.