As Janis put it, "Groupthink refers to a deterioration of mental efficiency, realitytesting and moral judgment that results from in-group pressures." Kennedywanted to overthrow Castro and his subordinates knew it - which meant thatthey, as a group, were not acting and thinking as intelligently as they could be.
By directly involving himself in the decision making, Kennedy caused hissubordinates to come up with a plan that pleased him rather than one thatmade the most strategic sense.
President Kennedy proved capable of learning from his mistakes as his actionsin the wake of the next major crisis that occurred on his watch, The CubanMissile Crisis of 1962, prove.
He convened an Executive Committee of the National Security Council, orEXCOMM, composed of Vice President Lyndon Johnson, his brother RobertKennedy, then Attorney General, and other members of his cabinet.
Robert Kennedy took on the role of Devil's Advocate, and was tasked withvigorously arguing against contemplated courses of action in order to force thegroup to discuss and debate the contingent merits of different strategies.
By making well-considered moves, President Kennedy influenced his Russiancounterpart, Premier Nikita Khrushchev to tone down the crisis.
The best thing a leader can do to prevent Groupthink is to take a step backfrom his or her team, and allow the group to reach its own independentconsensus before making a final decision.