Final answer:
The United States rejected the Treaty of Versailles due to concerns that it would compromise their constitutional power and draw them into foreign disputes. This decision weakened the ability of the League of Nations to mediate and resolve international conflicts.
Step-by-step explanation:
The United States rejected the Treaty of Versailles and did not join the League of Nations for several reasons.
One major reason was that the U.S. Senate feared that joining the League of Nations would lead to the loss of their constitutional power to declare war.
Additionally, they were concerned about the potential for being drawn into foreign disputes and the desire of Britain and France to control the League.
The United States' rejection of the treaty and non-membership in the League weakened the organization's ability to mediate and resolve international disputes.