These tactics made USA look very unpopular in the eyes of Vietnamese people. This was a major issue, according to the fact that Viet Cong soldiers were dressed exactly the same as the civilians, and without the help of villagers it was very hard to distinguish Viet Cong from normal habitants. Also the leader of South Vietnam, Ngo Dinh Diem, who was supported by USA didn’t respect the civilians and their religion, which also decreased the popularity of USA in Vietnam.
The other very important factor was the experience of Viet Cong and their perfect tactic. Viet Cong had the support of most of the civilians, who were helping them to hide in the village, so USA soldiers could hardly find any of them. Viet Cong soldiers used the guerilla tactic. They had a wide range of underground tunnels, which helped them to quickly disappear inside the jungle.
USA also had very incompetent soldiers, mostly because they were coming to Vietnam only for one year. As soon as the soldier was gaining the experience in fighting in the jungle against guerrillas, they were sent straight back home. With the army full of rookies it was impossible to win against experienced guerrillas on their home ground.
American public was strongly against the Vietnam War, this stopped the government from a lot of movements that could have been done. The politicians were more concerned about being selected in the next elections, than to win the war. The Vietnam War was called “the media war” because the pictures and videos from Vietnam were sent all around the world and helped to change the minds of American public, which showed a strong opposition towards the war.
The last reason was the support given to North Vietnam by China and USSR. The two great Communist countries had their interest in the Vietnam War, because they wanted Vietnam to be the part of great Communist empire. Although Soviets and Chinese sent a lot of money and weapons, they didn’t send any troops.
In my opinion the most significant reason for the failure of USA was the strong opposition of the public. That stopped the government from making a lot of moves, which may be cruel but would definitely give them a great and huge victory over Viet Cong.
