For the first 150 years of its history the US avoided becoming involved with other countries what is this policy called?

The policy that characterized the United States' avoidance of involvement with other countries for its first 150 years is known as isolationism. This approach emphasized non-intervention in foreign conflicts and a focus on domestic issues. It was rooted in the belief that the U.S. should concentrate on its own development and avoid entangling alliances that could lead to war. The policy began to shift in the late 19th and early 20th centuries as the U.S. began to engage more actively in international affairs.