This A-list politician has top secret health problems. Several years ago they suffered a debilitating stroke that they still feel the effects of today. The reason they haven't publicly disclosed this information is because they feel it'll cause people to doubt their competence. It actually cost them a role in a President's administration.
Your Guesses: Tim Kaine / Hillary Clinton / Donald Trump
As Wikileaks has since proven, Hillary Clinton has a whole bunch of undisclosed health problems that even worry her closest aide, Huma Abedin.
One email in particular from Abedin to another confidant has Abedin claiming Clinton was 'often confused' and suggested in another email that a speech should be cut short because the former First Lady wouldn't have anything to lean against for support.
A few months after the blind item was posted, the controversial clip of Hillary's losing consciousness in public after the 9/11 memorial emerged online, which showed the former Secretary of State being slung in the back of van by her handlers immediately after passing out due to ill health.
I don't want to delve too much into this because the last thing I need is the DNC coming after me, but Hillary is far from in the best of health and that is the truth.