For most of its history, the United States pursued what came to be called, in the twentieth century, an isolationist policy. (The words "isolationist" first appeared in 1862 and "isolationist" in 1899, while "isolationism" as a word apparently was not used until 1922.) Although this often emotionally charged term acquired a variety of meanings, depending on who was advocating or opposing it, and when they were doing so, isolationism can be defined generally as an attempt to avoid involvement in Europe's political and military (but not economic) affairs. To be more specific, isolationism came to mean the refusal of the United States to commit force beyond the limits of the Western Hemisphere and to avoid military alliances with overseas powers. On the other hand, the expansion of America's commercial ties with Europe was almost always considered vital to the economic prosperity of the United States, and thus exempted from the isolationist tradition.1
The principles of isolationism were gradually broadened in the nineteenth and twentieth centuries to include the avoidance of action with other nations in the pursuit of goals favored by the United States, such as upholding the Monroe Doctrine in Latin America; an emphasis on preserving unlimited American sovereignty, for example, by excluding U.S. immigration and tariff policies from international agreements; and a rejection of international political organizations and judicial bodies, such as the League of Nations and World Court.2
For nearly a century and a half after America's alliance with France ended in 1800, the United States successfully avoided what Thomas Jefferson called "entangling alliances" with European nations. In the nineteenth century, the United States fought the War of 1812, the Mexican War, and the Spanish- American War without allies and without engaging in military action in Europe. And when the United States entered World War I in 1917, it fought as an "associate" of Britain and France, rather than as their ally. After the war, the United States reverted to isolationism by rejecting membership in the League of Nations and the World Court.