Nothing. Best way to fight a war in which "taking ground" is not the objective; killing the enemy where ever and when ever you find them (war of attrition). It worked great! Its simply that the public got tired of hearing about "the Nam" and got tired of being drafted to fight it...otherwise "the body count system' worked great.
In the Vietnam War the US opposed the invasion of South Korea by North Korea. The fighters from North Korea, who used guerilla tactics, were known as the Viet Cong.
Search and Destroy.
During the Vietnam War, the US strategy was "Attritition". This involved the tactics of "Search and Destroy", which was accompanied by the procedure of "counting enemy bodies", which resulted in the term, "body count".
Before the American used to think with their technology and firepower, they would protect the world from the communist. The Vietnam war proved that they were wrong.
The US DID change it's tactics in Vietnam. The war went FROM a guerrilla war TO a conventional war (tanks and B-52 bombers). Had President Kennedy lived, Vietnam very well could have been fought by the USN SEALS and USA Special Forces (Green Berets). Fighting fire with fire. When Kennedy died, the WWII Generals took over; and Vietnam went WWII style (jets fighting jets, tanks fighting tanks, etc.).
Wars previous to Vietnam, for the US, was taking ground. Because of the nature of this limited war, "taking ground" was replaced with "attrition (body counts)", which called for the TACTIC of "Search and Destroy."
Changed Vietnam from a guerrilla war into a conventional war when conventional US combat troops were deployed there in March 1965 & and the bombing of North Vietnam commenced under the code name of ROLLING THUNDER.
War tactics didn't change, much. Just the media coverage that the people seen in the states changed,
Search and destroy. Attrit the enemy; via air cavalry. A new war, with new machines...it all worked out well.
We were at war with Vietnam because they disagreed with us about something.
the us government withdrew all troops from Vietnam, because the enemies guerrilla tactics made it a one sided war. We were losing countless soldiers in a war that didnt directly affect us, until the american citizens protested over having their loved ones and countless others sent to a country on the other side of the world.
US strategy was primarily based upon "attritition", which resulted in the tactics of "Search and Destroy". A function which required the counting of enemy bodies, which in turn created the term, "body count". The Vietnam War, became a war of body counts.