Between 1941 and 1953, the United States of America assumed a leading role in the creation and early development of the United Nations. The historiography of the early United States and United Nations relations understandably focuses on the contributions of the presidential administrations of Franklin D. Roosevelt and Harry S. Truman due to their central roles in establishing the global organization. In these accounts, Republicans are cited as secondary players that were engaged in a party-wide civil war between liberal internationalists led by Senator Henry Cabot Lodge, Jr. and an outdated isolationist faction led by Senator Robert A. Taft. This thesis problematizes the traditional narrative and offers an alternative interpretation. It posits that a better way to frame the highly influential yet underappreciated Lodge-Taft United Nations debate is to understand it as a conversation between two long-standing traditions of American conservative internationalism. In doing so, this study highlights the complexities of Lodge and Taft’s competing positions over the preeminence enjoyed by the great powers of the United Nations Security Council. It also forwards the notion that the Lodge-Taft United Nations debate can only be fully appreciated by framing it within the context of a coevolutionary discourse between two working politicians, and against the backdrop of World War II and the early Cold War.