The debate over the treaty centered around a debate over the American role in the world community in the post-war era, and senators fell into three main groups. The first group, consisting of most Democrats, favored the treaty. Fourteen senators, mostly Republicans, were known as the "irreconcilables" as they completely opposed U.S. entrance into the League of Nations. 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. 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 U.S. sovereignty. 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, was particularly unpopular among reservationists. Despite the difficulty of winning ratification, Wilson consistently refused to accede to reservationists, partly due to concerns about having to re-open negotiations with the other treaty signatories.