Some of these irreconcilables opposed the treaty for its failure to emphasize decolonization and disarmament, while others feared surrendering American freedom of action to an international organization.[238] The remaining group of senators, known as "reservationists", accepted the idea of the League but sought varying degrees of change to ensure the protection of American sovereignty and the right of Congress to decide on going to war.[238]
Article X of the League Covenant, which sought to create a system of collective security by requiring League members to protect one another against external aggression, seemed to force the U.S. to join in any war the League decided upon.[239] Wilson consistently refused to compromise, partly due to concerns about having to re-open negotiations with the other treaty signatories.[240] When Lodge was on the verge of building a two-thirds majority to ratify the Treaty with ten reservations, Wilson forced his supporters to vote Nay on March 19, 1920, thereby closing the issue. Cooper says that "nearly every League advocate" went along with Lodge, but their efforts "failed solely because Wilson admittedly rejected all reservations proposed in the Senate."[241] Thomas A. Bailey calls Wilson's action "the supreme act of infanticide".