I’m pretty sure there was a huge worry for a nuclear war which caused a lot of americans to become paranoid. america took advantage of the cold war to push anti-communist propaganda which was called “the red scare”. it was VERY successful and despite russia not actually being communist (they were more state capitalist). but that’s why our grandparents, parents, adults, and even kids associate communism with stalin and russia
Western Europe valued imperialism. For example, Great Britain was known for the numerous colonies that they had. There is a quote that states, "The Sun never sets on Great Britain" meaning that they had so many colonies around the world that the Sun never set on them. In addition, countries such as France and Spain also imperialized especially in the New Worl. However, Eastern Europe was always less developed than Western Europe so they didn't have the power to colonize countries. I hope this help! Good luck!
Many settlers were willing to leave their homes and head west due to the dream of attaining a better life, usually thinking of the possibility of acquiring free or cheap land. Other ocassions were for example, the "gold rush" in which so many went to California in search of gold. Others went west hoping to find more freedom.