Between 1959 and 1970, the Ho Chi Minh Trail had become the key logistical artery for PAVN and the Viet Cong (VC), in their effort to conduct military operations to topple the U.S.-supported government of South Vietnam and create a unified nation. Running from the southwestern corner of North Vietnam through southeastern Laos and into the western portions of South Vietnam, the trail system had been the target of continuous U.S. aerial interdiction efforts that had begun in 1966. Only small-scale covert operations in support of the air campaigns had, however, been conducted on the ground inside Laos to halt the flow of men and supplies on the trail.