(b) Why did US involvement in the Vietnam War escalate? [6 marks]
One reason was the domino theory. This was President Eisenhower's theory in the 1950s that communism would start from the USSR and China and spread throughout Asia. This is because each country may be influenced by his neighbour. Overall, the US feared that if Vietnam became communist, neighbouring countries in Asia might fall to communism.
Another reason was the emergence of the Viet Cong. They were a communist group, whose support had increased due to hatred towards anti-communist governments, who helped to send supplies and reinforcements to Guerilla fighters who attacked American Air Force and supply bases. Their emergence led to President Kennedy sending more US soldiers to help Diem's regime to resist communism.
Finally, the Gulf of Tonkin resolution. This was a law passed by the US congress which gave the President power to 'prevent further aggression and achieve peace and security'. This resolution was passed as a result of North Vietnamese patrol boats attacking US ships in the Gulf of Tonkin.