Suez Crisis led to a withdrawal. U.S. President Dwight D. Eisenhower had strongly warned Britain not to invade; he threatened serious damage to the British financial system by selling the US government's pound sterling bonds. Historians conclude the crisis "signified the end of Great Britain's role as one of the world's major powers". The Suez Canal was closed from October 1956 until March 1957. Israel fulfilled some of its objectives, such as attaining freedom of navigation through the Straits of Tiran, which Egypt had blocked to Israeli shipping since 1950. As a result of the conflict, the United Nations created the UNEF
Frustration–aggression hypothesis unjustified condition participants. The authors concluded that unjustified frustration leads to greater level of aggression, compared to justified frustration, which, in turn, results in higher levels of aggression compared to the non-frustration situations. In 1964, Leonard Berkowitz stated that it is necessary to have an aggression stimulus to make aggression take place. Then in 1974 and 1993, he remodified the frustration/aggression hypothesis into a theory that removed the importance of aggressive cues to the aggressive behavior. Which is to say, extremely angry subject will show aggression even if the aggression cue is absent. The most provocative theory introduced by Berkowitz