After the Versailles conference, Democratic President Woodrow Wilson claimed that "at last the world knows America as the savior of the world!"
However, the Republican Party, led by Henry Cabot Lodge, controlled the US Senate after the election of 1918, and the senators were divided into multiple positions on the Versailles question.
It proved possible to build a majority coalition, but impossible to build a two-thirds coalition that was needed to pass a treaty.

A discontent bloc of 12–18 "Irreconcilables", mostly Republicans but also representatives of the Irish and German Democrats, fiercely opposed the treaty.
One block of Democrats strongly supported the Versailles Treaty, even with reservations added by Lodge.
A second group of Democrats supported the treaty but followed Wilson in opposing any amendments or reservations.
The largest bloc, led by Senator Lodge, comprised a majority of the Republicans.
They wanted a treaty with reservations, especially on Article 10, which involved the power of the League of Nations to make war without a vote by the US Congress.
All of the Irreconcilables were bitter enemies of President Wilson, and he launched a nationwide speaking tour in the summer of 1919 to refute them.
However, Wilson collapsed midway with a serious stroke that effectively ruined his leadership skills.

The closest the treaty came to passage was on 19 November 1919, as 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 end the chances of ratification permanently.
Among the American public as a whole, the Irish Catholics and the German Americans were intensely opposed to the treaty, saying it favored the British.

After Wilson's presidency, his successor Republican President Warren G. Harding continued American opposition to the formation of the League of Nations.
Congress subsequently passed the Knox–Porter Resolution bringing a formal end to hostilities between the United States and the Central Powers.
It was signed into law by President Harding on 2 July 1921.
Soon after, the US–German Peace Treaty of 1921 was signed in Berlin on 25 August 1921, and two similar treaties were signed with Austria and Hungary on 24 and 29 August 1921, in Vienna and Budapest respectively.
After the Versailles conference, Democratic President Woodrow Wilson claimed that "at last the world knows America as the savior of the world!" However, the Republican Party, led by Henry Cabot Lodge, controlled the US Senate after the election of 1918, and the senators were divided into multiple positions on the Versailles question. It proved possible to build a majority coalition, but impossible to build a two-thirds coalition that was needed to pass a treaty.
A discontent bloc of 12–18 "Irreconcilables", mostly Republicans but also representatives of the Irish and German Democrats, fiercely opposed the treaty. One block of Democrats strongly supported the Versailles Treaty, even with reservations added by Lodge. A second group of Democrats supported the treaty but followed Wilson in opposing any amendments or reservations. The largest bloc, led by Senator Lodge, comprised a majority of the Republicans. They wanted a treaty with reservations, especially on Article 10, which involved the power of the League of Nations to make war without a vote by the US Congress. All of the Irreconcilables were bitter enemies of President Wilson, and he launched a nationwide speaking tour in the summer of 1919 to refute them. However, Wilson collapsed midway with a serious stroke that effectively ruined his leadership skills.
The closest the treaty came to passage was on 19 November 1919, as 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 end the chances of ratification permanently. Among the American public as a whole, the Irish Catholics and the German Americans were intensely opposed to the treaty, saying it favored the British.
After Wilson's presidency, his successor Republican President Warren G. Harding continued American opposition to the formation of the League of Nations. Congress subsequently passed the Knox–Porter Resolution bringing a formal end to hostilities between the United States and the Central Powers. It was signed into law by President Harding on 2 July 1921. Soon after, the US–German Peace Treaty of 1921 was signed in Berlin on 25 August 1921, and two similar treaties were signed with Austria and Hungary on 24 and 29 August 1921, in Vienna and Budapest respectively.
Treaty of Versailles