In the early sixties the public opinion was favourable towards USA's involvement in the war. From 64-65 a poll showed that 80 percent of the population agreed with Johnson and were for the war. America at this time saw it's-self as the "good guys" in the war, the ones who were there to defend the Vietnamese from the evils of communism. Baring in mind that the war occurred at the height of the cold war and the propaganda was quite strong; there was an overall distrust of communism and the East. The Domino theory was also very popular and so people were prepared to let Johnson stop it at nearly any cost. And besides America had won every war it had ever entered into, and so how much harm could a third world country full of peasants and farmers do? America had other reasons for being so confident; they had the best army and air force in the world, and at the time they were the richest country in the world.
In 1967 Johnson introduced the Conscription Act. This was unpopular as people started to question why they were being sent hundreds of miles from home to fight a war that was nothing to do with America. Lots of people started to tear up their draft papers, even Bill Clinton destroyed his and refused to become part of the war. The Act for a period excluded people between the age of 18 and 21 and people who went to college. As this largely applied to the middle and upper class white section of society, this was seen as a deliberate act to fill the army with the lower classes and black people.
This war became known as the T.V war. Unlike the Korean War and World War Two, the American government decided not to censor it and let the press have free access. The result of this was to bring home live uncensored pictures of scenes like small children being burned alive by American napalm. This shocked the Americans back home, and as practically every home owned a TV set, these shocking images bombarded the public, and sympathy for the war fell.