Answer:
Isolationism is a doctrine practiced by the United States during a large part of its history with the objective of not intervening in external affairs that did not pose a real threat to their country.
The isolationist idea was still present in 1823 when President James Monroe articulated what would be known as the Monroe Doctrine: "In wars between Europeans, in matters that only concern them, we have never participated, because it does not correspond to our policy. Only when our rights are damaged or seriously threatened will it be when we will resent our wounds and make preparations for our defense. "
The United States managed to maintain a state of political isolation throughout the 19th century and the first part of the 20th. Few nations have been able to maintain such a position for such a long period of time. Historians argue that it is largely due to geographic reasons, given the physical distance between Europe and the USA.
The beginning of the twentieth century brought with it problems that occurred in Europe and the Pacific, and this would end in large part with the isolationist feelings of the United States. The annexation of the Philippine Islands during the Hispano-American War of 1898 displaced US interests to the western Pacific Ocean, at the gates of Japan. USA UU he did not know how to perceive the threats against his position of neutrality. This caused the submarine war of Germany during the First World War, whose objective was to avoid the arrival of supplies towards the British Empire. When the war ended, USA. he forgot his new alliances; both the Treaty of Versailles and the League of Nations found little support from Congress.