In the United States, isolationism was a foreign policy in the years following the end of World War I that lasted until the direct attack on American territory at Pearl Harbor by the Japanese on December 7, 1941. Prior to that, U.S. President Woodrow Wilson's 1916 re-election was helped considerably by the fact that he maintained an isolationist policy that kept America out of World War I until that time. In Europe, Switzerland is known for an isolationist foreign policy that has been demonstrated by the country remaining neutral in all conflicts since the 1515 Battle of Marignano.
The Tokugawa Shogunate in Japan enforced an isolationist policy in the middle of the 17th century that lasted until the 19th century. Contact with most foreign countries was prohibited except for limited relations with Korea, China, the Netherlands and the Ryukyu Islands. During this period, Japan experienced what is considered to be one of the longest lengths of time in history in which a country was not involved in an armed conflict with a foreign nation.
In 1949, after the end of a bloody civil war, the newly-formed People's Republic of China headed by Mao Zedong closed its borders to many foreign countries and entered a period of isolation during which its most significant diplomatic relationship was with the Soviet Union. The relationship between China and the Soviet Union began to unravel, by the 1960s, after continued efforts by Mao to obtain nuclear technology from the Russians proved fruitless. China's attempts to become self-reliant were also unsuccessful and radical economic reforms began to take place in the 1970s. This led to China opening its borders to both trade and diplomatic relations with non-communist nations.