Generals, the old adage goes, are prone to fighting the last war. Political leaders and the people they represent typically prefer to avoid armed conflict, seeking, in effect, to avoid the last war.
So it was with the United States and the two world wars of the twentieth century. In the wake of each, the U.S. government, with public support, adopted a foreign policy designed to avoid the necessity of waging another such war; but the approaches the country adopted after the two conflicts were diametrically opposed. Disappointed by the results of World War I, America disengaged from European security so as not to become entangled in another conflict on that continent. That approach failed. The country was drawn into World War II, and in its aftermath took an entirely different tack, becoming deeply engaged in Europe and carrying out a successful policy of deterrence toward the Soviet Union, which had replaced Nazi Germany as the major challenge to American and European security.
