1954 in the Vietnam War 5 April The National Security Council met again to consider U.S. intervention at Điện Biên Phủ. The Army, including Army Chief of Staff General Matthew Ridgway, was negative, stating that U.S. intervention would require 7 army divisions and heavy air support. 7 April President Eisenhower used the phrase "falling dominoes" in a press conference. This was the origin of the domino theory which postulated that if Vietnam became communist the other nearby states would soon follow. The domino theory was a prominent justification for the Vietnam War in the United States during the 1960s. 14 April Secretary of State John
Non-intervention in the Spanish Civil War follow a policy of non-intervention, but did not announce it officially. This isolationism on the Spanish war would later be identified as disastrous by Under-Secretary of State Sumner Welles. Five days later, the Glenn L. Martin Company enquired whether the government would allow the sale of eight bombers to the Spanish Republican Air Force; the response was negative. It also confirmed it would not take part in several mediation attempts, including one by the Organization of American States. Mexico soon became the first nation to openly support the Republicans. On 15 August, the United Kingdom banned exports of war material