In the course of American history we have employed many tactics and ploys to keep our nation and our nation's beliefs safe. Isolationism, Imperialism, and Intervention all come into play at least once during each of the wars our country has fought in.
Isolationism: it's basically a policy of remaining apart from the affairs or interests of other groups to prevent unnecessary wars. It mostly involves politics rather than trade.
The most prominent example of American Isolationist Policies is during WWII, when Isolationists advocated non-involvement in European and Asian conflicts and non-entanglement in international politics. This kept America out of WWII until the Japan`s attack on Pearl Harbor in 1941 which brought the United States into the war on the Allied side.
Next up is Imperialism: it is another policy, only it involves extending a country's power and influence through diplomacy or military force. It mainly influences our economy and it also helps to keep the peace between the weaker nations.
U.S. imperialism took many different forms in the 20th century, ranging from colonies in Puerto Rico and the Philippines to protectorates in Cuba, Panama, and other countries in Latin America, and open door policies such as that in China. Formal colonies would be ruled with U.S.-appointed colonial governors and supported by U.S. troops. During WWII the Japanese attacked the american colonies in the Philippines and drove the United States out. The General McArthur declared as he was evacuated from the Philippines that" I shall return" and he did.
And last but certainly not least Intervention: interference by a country in another's affairs to improve a situation. Mainly to help maintain order and to stop dictators.
The best examples of this are immediately after WWII and it was called the Cold War foreign policy. The United States and its allies used it to prevent the spread of communism as much as possible without starting a war with the Soviet Union aka: Russia. Vietnam was really just a battle of democracy vs communism.
Hopefully this answer should help you
