The US justified its military intervention in Vietnam by the domino theory, which stated that if one country fell under the influence of Communism, the surrounding countries would inevitably follow. The aim was to prevent Communist domination of South-East Asia.The USA became involved in Vietnam because it feared the spread of communism. The USA were unable to defeat the Vietcong and were met with growing opposition to the war back home.
Republicans were especially angered by the Dred Scott v Sandford decision because the supreme court ruled that congress didn’t have the power to ban slavery.
