CORDS was designed to combat the peasant-based Maoist insurgency of the VC in South Vietnam. "One of the ironies of the Vietnam War is that the southern-rooted insurgency that prompted U.S. military intervention in the first place was significantly pacified – although by no means extirpated – by the time the last major U.S. ground combat forces departed South Vietnam." The years, after reverses during Tet, from 1969 until early 1972 saw "uninterrupted gains in population security throughout South Vietnam and further erosion of the VC. The VC had only a minor role in the 1972 and 1975 communist offensives, the latter resulting in the conquest of South Vietnam by the conventional military forces of North Vietnam.