In 1956, most of Southern members of Congress signed the Southern Manifesto, which called for the overturning of Brown. Eisenhower appointed five justices of the Supreme Court of the United States. Hopes for reaching a nuclear agreement at a May 1960 summit in Paris were derailed by the downing of an American U-2 spy plane over the Soviet Union.The Eisenhower administration, initially thinking the pilot had died in the crash, authorized the release of a cover story claiming that the plane was a 'weather research aircraft' which had unintentionally strayed into Soviet airspace after the pilot had radioed 'difficulties with his oxygen equipment' while flying over Turkey. Further, Eisenhower said that his administration had not been spying on the Soviet Union; when the Soviets produced the pilot, Captain Francis Gary Powers, the Americans were caught misleading the public, and the incident resulted in international embarrassment for the United States. The Senate Foreign Relations Committee held a lengthy inquiry into the U-2 incident.