During the 1930s, the United States wanted very much to avoid war. It felt that it had been dragged into World War I and did not want such a thing to happen again. Therefore, there was great support for isolationist policies and these policies came to dominate US policy.
This can be seen most clearly in the Neutrality Acts that were passed in this decade. These acts set out a number of restrictions on US interactions with countries that were at war with one another. Neutrality Acts (each more strict than the one before) were passed in 1935, 1936, and 1937. The passage of these sorts of acts, and the retreat from efforts at things like arms control that had dominated policy in the 1920s, showed that isolationism was the dominant force in US policy in the 1930s.
The United States clearly believed in a policy of isolationism in the 1930s. The Nye Committee examined reasons why we joined World War I. The main conclusion of the Nye Committee was that we joined the war so businesses could profit. The American people weren’t too happy about this. Congress took steps to prevent us from getting dragged into another war for a similar reason.
There were several neutrality laws passed in the 1930s. The Neutrality Act of 1935 prevented us from selling weapons to countries at war. In 1936, this was expanded to include countries fighting a civil war. In 1937, another neutrality law was passed. This law said we could sell nonmilitary supplies to countries at war only on a cash and carry basis. These countries would have to pay cash for the items they bought, and they would have to carry the items on their own ships. It also reinforced the concept that we couldn’t sell war materials to countries at war.
There were other factors influencing our policy of isolation. We were in the middle of the Great Depression. Most of our attention had to be focused on dealing with handling the Great Depression. Americans weren’t too interested in what was happening in other parts of the world when they were struggling at home. We also weren’t ready to take positions on world issues that could lead us to war. World War I ended in 1918, and people weren’t ready to possibly fight another war so soon.
For these reasons, the United States pursued a policy of neutrality for most of the 1930s. The passage of several neutrality laws reinforced this policy.