It happened after he curtailed an 8,000-mile national tour to promote U.S. membership in the League of Nations. The trip cost Wilson his health.
Wilson's tour had its parallel in the tour that Inez Milholland Boissevain undertook in 1916 to campaign against Wilson for not supporting the Anthony Amendment.
Both Inez and the President suffered constant headaches during their tours. Both finally collapsed – Inez in October 1916 in Los Angeles, Wilson in September 1919 in Pueblo, Colorado.
Both failed in their mission, but contributed to it, and had their health not given out might have seen their goals achieved. Inez failed to defeat Wilson, although the California vote was so close the results were weeks in becoming final – but her death was the inciting incident in the picketing of the White House, and the Anthony Amendment was passed with Wilson's support in 1919, with ratification as the 19th Amendment the following year.
Similarly, Wilson's campaign for membership in a world body was ended by his collapse, but was achieved after his death in 1945, with U.S. membership in the United Nations.
After his collapse, Wilson returned to Washington, but suffered a massive stroke on October 2. Wilson’s wife Edith blamed it on Wilson's Republican Congressional opponents, because they attacked Wilson personally on issues relating to the League of Nations.
Edith kept quiet the extent of Wilson’s incapacitation. While Wilson lay in bed motionless, Edith is reported to have screened his messages, and sometimes signed her husband's name without consulting him.
In her memoirs she said she acted as her husband's steward. Her husband continued to serve as President and partly regained his health, but remained paralyzed on one side. He did not return to his campaign for U.S. membership in the League, and the United States never joined, since Republican Warren Harding was opposed and he was elected President in 1920. Wilson died in 1924.