The First Indochina War took place across French Indochina and eventually led to French defeat and the signing of a peace accord for Laos at the Geneva Conference of 1954. In 1955, the US Department of Defense created a special Programs Evaluation Office to replace French support of the Royal Lao Army against the communist Pathet Lao as part of the US containment policy.
In 1960, amidst a series of rebellions in the Kingdom of Laos, fighting broke out between the Royal Lao Army and the communist North Vietnam-backed, and Soviet Union-backed Pathet Lao guerillas. A second Provisional Government of National Unity formed by Prince Souvanna Phouma in 1962 proved to be unsuccessful, and the situation steadily deteriorated into large scale civil war between the Royal Laotian government and the Pathet Lao. The Pathet Lao were backed militarily by the NVA and Vietcong.
The North Vietnamese invasion of Laos, by the Moscow-backed Vietnam People's Army, and post-Vietnam War occupation of Laos, continued in the 1960s, 1970s and 1980s.
Laos was a key part of the Vietnam War since parts of Laos were invaded and occupied by North Vietnam for use as a supply route for its war against the South. In response, the United States initiated a bombing campaign against the North Vietnamese positions, supported regular and irregular anticommunist forces in Laos and supported South Vietnamese incursions into Laos.