President Calvin Coolidge, who assumed office after Harding's death in 1923, maintained his predecessor's position of international neutrality, preferring to concentrate on the growth and maintenance of his own country. The only issue that managed to penetrate the nation's staunch isolationism was the Kellogg-Briand Pact, which the United States signed along with sixty-one other countries, including Germany, Japan, and Italy. In so doing, the nations promised never to resort to war as an instrument of national policy. But as future events would show, the pact, merely a promise with nothing to back it up, ultimately proved to be worthless (as did the League of Nations, which, in the end, was unable to stop the Axis powers from taking the actions that led to world war).

Map 1-1 U.S. foreign trade routes. The thickets of the trading veins extending from the United States will soon be cut off due to the war.

Map courtesy of the National Archives (Travel and Ship under the American Flag, Record Group 178, Maritime Commission)

Sadly, America's isolationist attitude served only to benefit those nations that made war a part of their expansionist policies. For example, when Japan finally decided to invade a nearly helpless China in 1931, President Herbert Hoover, a Quaker by faith, immediately ruled out military force to stop Japan's aggression. Instead, he expressed “moral condemnation” and told the world the United States would not recognize any international changes that conflicted with its Open Door policy or the Kellogg-Briand Pact. Faced with moral censure but little else, Japan's militarists continued their vicious assault against China, which included the invasion of Manchuria in 1931 and, a year later, a shocking bombing attack on Shanghai, one of China's most important trade centers, which killed thousands of civilians.

Similar problems soon occurred in Europe and Africa. In 1935, Italy invaded Ethiopia in Mussolini's quest for a contemporary Roman Empire. The League of Nations tried to quell the aggression with economic sanctions, but they did little good. Mussolini, like his counterparts in Japan, assumed that no one would try to stop his bully tactics, and he was right.

Germany also began stretching its militaristic wings in 1935, when, in direct violation of the Treaty of Versailles, it began to create its powerful air force, the Luftwaffe, and a new navy. The following year, German troops occupied the Rhineland, which had been designated a demilitarized zone. This, too, was in direct violation of the Treaty of Versailles. As with Italy and Japan, however, no one — least of all the United States, which continued to be bound by its isolationist attitudes — did anything to halt Germany's increasing aggression.