The Senate's opposition to United States

membership in the League of Nations was based

mainly on the

(1) cost of membership dues

(2) failure to give the United States veto power

(3) fear of being drawn into future wars

(4) concern that United States businesses would

be damaged

The Senate's opposition to United States membership in the League of Nations was based mainly on the 3. fear of being drawn into US wars. The United States was only just emerging from its long history of isolationism and thus when policymakers were faced with potentially tethering the nation to an international body, they were very cautious and ultimately rejected the ratification of the treaty.