Japan proposed that the treaty include a racial equality clause. Wilson was indifferent to the issue, but went along with the strong opposition that came from Australia and Great Britain.When Wilson traveled to Europe to settle the peace terms, he visited Pope Benedict XV in Rome, making Wilson the first American President to visit the Pope while in office. For his peace-making efforts, Wilson was awarded the 1919 Nobel Peace Prize.
When Wilson arrived back home in the United States, he faced the challenge of getting the Treaty of Versailles (and the United States' participation in the League of Nations) passed through Congress. On September 3, 1919, Wilson embarked on a cross-country speaking tour in an attempt to rally the nation to his support. He was met with intense opposition from Irish Catholics and Germans, most of them Democrats. Over-worked and over-tired, Wilson suffered a series of debilitating strokes and had to cancel the rest of his trip on September 26, 1919. He became an invalid in the White House, closely monitored or controlled by his wife. Republicans under Senator Henry Cabot Lodge controlled both houses of Congress after the 1918 elections.
The key point of disagreement was whether the League of Nations would diminish the power of Congress to declare war. The Senate was divided on the question. It became impossible to build the two-thirds coalition needed to pass a treaty.In mid-November 1919 Lodge and his Republicans formed a coalition with the pro-Treaty Democrats, and were close to a two-thirds majority for a Treaty with reservations, but Wilson rejected this compromise and enough Democrats followed his lead to permanently end the chances for ratification. Wilson's biographer John Milton Cooper suggests that Wilson's stroke on Sept 25, 1919, had so altered his personality that he was unable to effectively negotiate with Lodge. According to Cooper, the psychological effects of a stroke were profound. Cooper wrote:
"Wilson's emotions were unbalanced, and his judgment was warped....Worse, his denial of illness and limitations was starting to border on delusion."
Following his strokes, Wilson became less trustful of the press and stopped holding press conferences. A poll of historians in 2006 cited Wilson's failure to compromise with the Republicans on U.S. entry into the League as one of the 10 largest errors on the part of an American president.