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
US signals intelligence in the Cold War a decade of world change, with changes in Cold War alliances and emphasis, the first submarine attack since World War II in the context of a regional war involving extensive power projection, low- and medium-intensity operations, and continuing national policy development. Roughly from the late 1980s on, there was cooperation between the US and the PRC in collecting SIGINT of mutual interest, principally against Russia. It is believed that the Qitai and Korla sites, in Xinjiang (Sinkiang) are operated jointly by the Chinese and the US CIA Office of SIGINT Operations against Soviet missile tests and space launches, but their