During the First World War, the US became the largest supplier of food, manufactures and weapons to Europe. In this context, at the end of the war there was a relationship of dependence, where the US needed the market of Europe to dispose of its great production, and war-torn Europe depended on the American supply.
However, the European economy was devastated while the US was at its peak and created an overproduction that did not find enough consumer market, causing the economic crisis that would become the great depression.