Disputes between progressives and conservatives have been a regular feature of American politics. Conservatives have traditionally favored a limited federal government that leaves the bulk of governing to state and local authorities, whom they argue are more closely attuned to the interests and character of the surrounding populace. From this perspective, federal guidelines issued by Washington, DC, relied on abstract and uniform principles that often flew in the face of local traditions. Conservative sensibilities also tended to oppose interventionist foreign policy, which served to enhance federal power, and preferred practical knowledge and traditional wisdom over abstract principles.

World War II scrambled these categories, especially after the Japanese attack on Pearl Harbor. It now seemed impossible for a major political figure to profess indifference to the outside world, much less to deny the critical role of the federal government in detecting and combating threats to the US. The dangers posed by Imperial Japan and Nazi Germany were sufficiently broad as to unite American liberals and conservatives. Conservatives accepted an alliance with the Soviet Union as necessary to defeat Hitler, and liberals accepted the US’s continued support of British imperialism for the same reason.

At the end of the war, the Soviet Union dominated half of Europe, while the British and other colonial empires teetered on the brink of collapse.