The Viet Cong (VC) were Communist sympathizers living in SOUTH Vietnam. Very organized, wearing what-ever uniforms and using what-ever weapons they could get their hands on; and fighting primarily as...
They were tough when the US went after them with jets, tanks, and infantrymen; but they weren't so tuff when SEALS/SF (Special Forces-Green Berets)/LRRPS (Long Range Reconnaissance Patrols)/and US...
US troops retaliated with firepower. Just one NVA or VC popping off a few rounds at GIs could bring in artillery, naval artillery, helicopter gunships, and jet strikes. Not to mention tanks and ACAVs...