The Americans who were then used to being isolated from the affairs of Europe also had serious reservations on the commitment that the United States will put up with. Wilson might still have won the approval if he had agreed to some relatively minor changes in the language of the treaty, but then Wilson refused to yield stating that the United States had a moral obligation to respect the terms of the agreement precisely as they stood. And although Wilson decided to appeal to the public, the public interest then in the peace process on international matters was said to fade because of the severe recession experienced by the American economy.

In all these, it is very evident that partisan politics played a significant role in the United States making its international commitment. Both President Wilson and the opposition were unable to make a good compromise mainly because the opposition wanted to maintain the sovereignty of the United States and as much as possible isolate the country from any political or economic commitments. The isolationist policy of the opposition and the stance of President Wilson to respect the terms of the agreement were at different ends and were unable to agree on the commitments that President Wilson wanted to pursue. Furthermore, concerns about their own economy was the primary concerns of most Americans, that the public sentiment in involving the United States with the League of Nations was also far from what the Americans wanted at that time.

These were the main reasons for the rejection of both the League of Nations and the Treaty of Versailles. In that even though the United States, mainly through President Wilson, was one of the proponents for the creation of international commitment to peace, partisan politics and concerns about the sovereignty of the United States, were the reasons for the defeat and rejection of both the treaty and the League.