The united states senate rejected the treaty of versailles mainly because the treaty

The United States Senate rejected the Treaty of Versailles mainly because the treaty would force the U.S. to enter the League of Nations and get involved in international conflicts.

Explanation:

The League of Nation was an international peacekeeping organization, proposed by American President Wilson and included in the Treaty of Versailles, whose aim was to develop cooperation among the member's nations and to guarantee them peace and security through open diplomacy and global consensus.

Signing the Treaty of Versailles, then, would also mean to be part of the League of Nation and be bound to make alliances and defend their members if they were attacked. The U.S. Senate, fearing that the League of Nations would drag the country into some future world conflict, determined to reject the treaty, to adopt an isolationist policy and focus on domestic issues instead.