The correct answer is the following.
After the conclusion of World War 1, the United States government applied a foreign policy of isolationism focusing on internal issues instead of external ones. This was economic an political doctrine followed by President Harding and President Coolidge- Economically, the United States limited foreign competition and imposed elevated taxes on imports. Politically, the U.S. did not want to be part of the League of Nations.
But the problem was that the United States could not maintain that isolation for much longer due to the necessity to trade with different economies in the world that produced goods that could not be found or not in the necessary amounts needed for the U.S. consumption. Regarding investments, there was foreign money invested in the U.S. and U.S. money invested in Europe. Isolationism was not easy to maintain.
