AT THE END OF DECEMBER 1967, a month before the communist Tet Offensive attacks throughout South Vietnam, approximately 225,000 Viet Cong and North Vietnamese fighters were operating in South Vietnam. They consisted of 68,000 full-time combat soldiers born in North Vietnam, 47,000 Viet Cong combat soldiers born in the South, 37,000 Southern-born Viet Cong administrative personnel who ran the communist shadow government in many parts of the country and 71,000 part-time Viet Cong guerrillas born in the South, according to estimates by Military Assistance Command, Vietnam.
MACV calculated that the communists committed 124,000 combat troops and guerrillas to the 1968 Tet Offensive—84,000 in the initial battles of Jan. 30-31, plus 40,000 over the next several weeks. About half of them served in North Vietnamese units, and the rest belonged to…