"Kennedy was praised nationwide, even by his Republican critics, for his masterly handling of the Cuban missile crisis, a response Schlesinger characterized as a "combination of toughness and restraint." Yet few discussed what could have happened had he failed. Historian Louise FitzSimons points out what many preferred not to think about: "In the flush of success and relief from danger, Kennedy was determined to force Krushchev's total capitulation- no matter the cost." During the height of the crisis, the president himself placed the likelihood of disaster at "somewhere between one out of three and even," and lamented that the world's children might not live out their lives. Ironically, the enhanced short-term prestige that Kennedy experienced in the wake of the Cuban missile crisis only produced greater long-term insecurity for his country. The humiliation Krushchev suffered at the hands of Kennedy during the missile crisis contributed to his removal from power in October 1964. The new Soviet leadership, headed by Leonid Brezhnev, was determined to avoid a repetition of the humiliation Krushchev had experienced. Beginning in early 1965, the Kremlin embarked on a massive expansion of the Soviet nuclear arsenal that would enable the Soviet Union to achieve nuclear parity with the United States by the end of the decade. in addition, Kennedy's triumph in the Cuban missile crisis contributed to the development of what historian William J. Medland has called an "arrogance of power," a belief that the United States had the communists on the run. This new attitude helped to explain the growing U.S. involvement in Vietnam."