In the air campaign over the DRV, the United States failed to realise that bombing a country that had little industry and a large population that was dedicated to victory will not bring them to their knees. The air campaign over South Vietnam did more damage than good to the war effort as bomb that were indiscriminately dropped in the countryside recruited more Vietcong than they killed.
When violence erupted in South Vietnam in the mid-1950s, the government under Ngo Dinh Diem initially faced an internal threat from VC guerrilla forces. These VC forces typically engaged in hit and run attacks and terrorism until the VC could gain enough strength to amass and supply larger conventional forces that could challenge and defeat the U.S trained and equipped ARVN forces. Facilitating this transition in VC strategies and tactics, North Vietnam increased its support of the VC by expanding the Ho Chi Minh Trail in 1959.
Although the VC formed larger, more conventional units, the war changed dramatically in 1964 with the Gulf of Tonkin Incident, which resulted in the Asia resolution that authorized the President to do whatever necessary in order to assist "any member or protocol state of the Southeast Asia Collective Defense Treaty."   The United States started bombing North Vietnam and in the following year become more heavily involved in the ground war in South Vietnam. At the same time, North Vietnam decided to commit more material and larger number of ground troops to the war in the south.
After the United States introduced ground units in 1965, the NVA/VC quickly realised that they will never have enough firepower to truly challenge the United States on the battlefield, and as long as the United States remained committed to sending more soldiers to fight in Vietnam, the NVA/VC could never win an outright military contest. So, instead of trying to match the U.S superiority in firepower, they chose to use their strongest ally -time- against the U.S./ARVN forces. One of...