- Isolationist sentiment: Many Americans were disillusioned by the heavy cost and human toll of World War I, and were determined to avoid future foreign entanglements. They believed that the US should focus on its own domestic affairs and economic recovery, rather than getting involved in European conflicts.
- Non-interventionist policies: The US government, under the leadership of President Franklin D. Roosevelt, pursued a policy of non-intervention in the early years of World War II. This was partly due to the strong isolationist sentiment in the country, but also to the belief that the US could best serve Allied interests by providing material support (such as Lend-Lease aid) without directly entering the war.
- Lack of immediate threat: At the start of the war, the US did not perceive an imminent threat to its own security from the European conflict. The focus of the fighting was primarily in Europe, and the US was geographically distant from the main battlefields.
- Public opinion: Public opinion in the US was divided on the issue of intervention in the war. While many Americans were sympathetic to the Allied cause, there was also strong opposition to the idea of the US entering the war. This opposition was based on a variety of concerns, including the potential costs and sacrifices involved, as well as the fear of getting dragged into a prolonged conflict.
- Appeasement: Some US policymakers, including President Roosevelt, initially believed that the best way to avoid war was to appease the Axis powers (Germany, Italy, and Japan) by making concessions and trying to avoid provoking them. This approach was later abandoned as it became clear that appeasement was not working and that the Axis powers were determined to pursue their aggressive goals.