McArthur?
He died in 1964 and wasn't involved in 'Nam insofar as I can see (he was dismissed for insubordination during the Korean war IIRC and retired in the same year).
I'm not sure what year you define as the start of the Vietnam war, anyways; if it's the Gulf of Tonkin incident in '64, then the Vietcong weren't driven out by any historical site I've seen; the US ended up allowing napalm in '65 and authorising an increase to 400,000 troops in '67. I've read nothing that suggests the Vietcong had been defeated as such (bar the loss of 'visibility' due to a switch to guerilla tactics having been comprehensively defeated by US air dominance in initial battles in '65); and if you use 65 as the start date of ground fighting and hence the war, the VC / North Vietnam were definately still fighting in '67 (and launched an ultimately doomed siegewith 20,000 troops upon Khe Sang in January '68).
And then there's the Tet offensive, when the supposedly crippled VC forces captured Hue. Although ultimately driven back, it shown that the war wouldn't be ending soon and was a propaganda victory (given that war is as much about politics as military strength).
EDIT; IIRC there were US troops operating in Laos and Cambodia anyways; the US launched bombing of Laos from 1968 to 1972, and also bombed Cambodian. It then invaded Cambodia in 1970 with South Vietnamese troops and secretly sent Marines into Laos in 1969 (South Vietnam would later invade in 1971).