Clandestine Thai military activities in Laos served two main objectives. The original objective was to preserve the non-communist Royal Lao Government (RLG), which was severely threatened by the communist Pathet Lao and the North Vietnamese. The second objective, which became increasingly important in the late 1960s and early 1970s, was to support secretly the US military activities in South Vietnam and indirectly defend the South Vietnamese government against the communists by interrupting the Ho Chi Minh Trail, the lifeline of the communists running through the dense jungles of Laos and the north-eastern part of Cambodia, linking the revolutionary movement in the fields with the supply base in North Vietnam