The reasons why refugees and immigrants came to the United States are related to the complicated history of their homelands.

Colonization and Occupation by Foreign Powers
Western nations have been interested in colonizing Southeast Asia for centuries due to its strategic political location and natural resources. The Chinese dominated the region for a thousand years. Europeans sailed there in the 1500s to buy silk, tea, and spices. French Catholic missionaries entered the region to convert the population in the early 1600s. By 1887 France had formally colonized the region, which would become the countries of Vietnam (divided into Tonkin, Annam, and Cochin China at the time) and Cambodia. In 1893 Laos was added, and the territory was renamed French Indochina or the Union of Indochina. Anti-French resistance and insurrections followed, such as that of the highland Lao fighters in the early 1900s. The region was occupied briefly by Japan during World War II from 1941-1945.

The First Indochina War
France tried to recolonize the region in 1945 with financial backing from the U.S. The First Indochina War began in 1946, when Viet Minh nationalist forces struggled for independence from French colonial rule. Battles took place in Vietnam and Laos. In 1954 the First Indochina War ended with a meeting chaired by Great Britain and the Soviet Union, with representatives of the United States, China, Cambodia, North Vietnam, South Vietnam, and Laos also in attendance. The Geneva Peace Accords were signed, calling for an end to hostilities in Indochina, establishing neutrality in the region, and authorizing interim governments until general elections could be held.

France transferred sovereignty to Cambodia and Laos , granting them full independence, but Vietnam remained under French colonial administrative control. The treaty also established a demilitarized zone at the 17th parallel that partitioned communist-controlled North Vietnam from pro-democracy South Vietnam ; this was intended to be temporary until elections could be held in 1955.