 In most cases , the defense against the communists was a South Vietnamese affair . Local militia or ARVN forces , supported by the National Police , usually drove the attackers out within two or three days , sometimes within hours ; but heavy fighting continued several days longer in Kon Tum , Buôn Ma Thuột , Phan Thiết , Cần Thơ , and Bến Tre . The outcome in each instance was usually dictated by the ability of local commanders — some were outstanding , others were cowardly or incompetent . During this crucial crisis , however , no South Vietnamese unit broke or defected to the communists . 
