Presidential Health

This article from Slate discusses a new theory about FDR's health in his final days. A new book alleges that FDR actually died from a cancer that he and his doctor's knew about before he ran for his fourth term.

Conspiracy theories like this bring up important issues of presidential transparency. How much are president's and their doctors obligated to reveal about their health? When such a private issue can affect the nation so greatly, is it better to be honest or to uphold the image of the president? JFK kept his health problems private, going out of his way to appear athletic and energetic. After Reagan was shot, he walked into the hospital without help. Bush Sr. was mocked for vomiting on the Japanese Prime Minister. The McCain campaign was criticized for minimizing McCain's melanoma battle.

If FDR really did have cancer, why would he decide to run for a fourth term? How much did it affect his selection of Truman as a running mate? How much does a president's health factor into his decisions?