I've had just about enough of these presidents and their secret diseases! Divulge your debilitating health problems, you megalomaniacs! This isn't tsarist Russia!
When Wilson returned from Paris in the spring or summer of 1919, he faced an uphill battle both politically and physically. The peace process had exhausted him, and his doctor was begging him to take some time off, but he returned to find that Henry Cabot Lodge (who is just ONE OF THOSE SENATORS) was determined that Congress not ratify the Treaty of Versailles.
While Lodge worked the votes in Congress, Wilson decided to go on a whistlestop tour of the US to rally support for the Treaty and the League of Nations from the people themselves, whose support he had lost during his months abroad. His doctor, Grayson, begged him not to do this. He'd been having what Grayson called "cerebral episodes" with increasing frequency, and going on a grueling train trip in the middle of the summer with stops to give long speeches, seemed like a recipe for disaster. Wilson couldn't be dissuaded, and basically told Grayson that he was willing to kill himself for the League.
The trip was cut short when Wilson collapsed after a speech in Pueblo, Colorado, and Wilson rushed backed to Washington to rest. In October of 1919 Wilson had a serious stroke, and was bedridden for months. He didn't leave the White House grounds for something like six months. He didn't speak to any of his Cabinet until February. He saw almost nobody besides his wife, Grayson, White House usher Ike Hoover, a nurse, and various White House staff. But absolutely no government officials.
During this time, his wife Edith acted as his gatekeeper, taking messages for him and deciding which of them he needed to know about (very few). The country was informed that the president was sick and needed to rest, but nobody knew exactly how serious it was. The Cabinet kept meeting without him, which made Wilson mad, to which they responded SOMEONE NEEDS TO RUN THE COUNTRY, DUDE.
Throughout this time, Wilson would occasionally toy with the idea of ceding power to his vice president, a nice dude from Indiana from Marshall. But he and his doctor decided that he was able to "adequately perform" his duties as president, a decision he made based on the very limited view of what was going on in the government he got from Edith. Because Edith only told him about the issues he could easily handle from his bed, he assumed that he was easily handling the presidency. He was not. Federal appointments stayed open for months, new ambassadors couldn't start their jobs because Wilson couldn't accept their credentials, and the secretary of the interior hired a young guy named J. Edgar Hoover, who started wantonly deporting Russians on suspicion of communism.
Wilson was a great man, and the fact that his body failed him at the most crucial moment of his presidency is truly a tragedy, but it makes me mad when the presidents do this. I've talked about the presidential gaze before, how entering the office gives you a higher level of perspective, but I also think it convinces these dudes that they are innately, divinely presidential. Wilson convinced himself that even in a drastically debilitated state, he needed to be the president.
Then he swung from telling Grayson he was going to cede power to Marshall, to saying that he was going to run for a third term, in case you needed to know how much denial he was in.
The Democrats got slaughtered in the midterms, and Wilson regained just enough strength by mid-1920 to be what biographer Berg called "the lamest of all lame ducks in American history," which is a Wilson-can't-walk-without-a-cane joke. Although Edith and Wilson maintained that his mind remained sharp for the duration of his presiency, Grayson and Ike Hoover both later admitted that he was never himself after Pueblo.
The best thing to happen to Wilson at the end of his life was that his successor, Harding, was a bona fide disaster, so public opinion rushed back to him almost immediately. By the time he died in 1924, he was the most popular man in America again.