After the United States Forces defeated every attack on provincial capitals, Walter Cronkite, in full gravitas, announced to the country that we could not win the war. That, more than perhaps any other broadcast, fueled antiwar sentiment in the States.
The Viet Cong never recovered after that defeat (Tet), instead, NVA troops invaded and infiltrated in the later part of the war, and after Democrats in Congress cut funding for South Vietnam's defense, overran the country.
But the propaganda victory had been won, thanks to the American Media.
The blood of millions of Vietnamese, Cambodians, Americans, and others is on his hands.