ABSTRACT
The idea that neutrality might be an invalid or immoral stance was totally alien to the vast majority of Americans in the 1930s. However, between 1933, when Franklin Delano Roosevelt became president of the USA, and 1942-3, when it became clear that the Allies were going to win the Second World War, there was a transformation that made the USA a more active participant in international affairs, encouraged its realist tradition, and turned its leaders against neutrality. By 1942 US practice reflected the view that there was a diminishing space for neutral trade and neutrality itself in total war. The logic of both collective security, which placed responsibility on all to respond to aggression, and total war undermined neutrality. Soon Americans justified their assault on neutrality in the same moralistic manner that they had championed neutral rights to trade, though they also acted on the basis of realist perceptions of how their national interest could best be promoted. This transformation had major implications for the use of economic sanctions and embargoes, not only in conventional total war but also later in the Cold War, with its ever-present threat of total nuclear war.
