Answer:
Before World War I the U.S was seen as weak it had moved away from the European style of leadership. With no king or emperor European power saw the U.S as having no leadership and could be easily pushed around. But as WW1 kicked off. The U.S industrial and agricultural sectors boomed as they begain to trade weapons, food, tools to both sides. They easily became the worlds #1 economy and could start to build their own military power. Once the U.s joined the war though is when it military force was shown off. The U.S was able to conscript men faster than anyone expected. This caused the germans to start the 100 days offensive. To try and break the French lines before the U.S troops could land in France. After the war all other countries survived off of the American industry proving how strong the U.S could be. During the Great Depression after the U.S economy fell so did all other countries as trade almost completely disappeared.
I hope this helps!!!