Perhaps John F. Kennedy's greatest legacy is the optimism he brought to the Oval Office, epitomized in his famous 1961 inaugural address in which he stated, "Ask not what your country can do for you; ask what you can do for your country." His wife, Jacqueline Kennedy (later Onassis), also added a great deal of glamour and culture to the life of the White House.
You should sort through the information about his presidency to decide what you think are his successes and failures, but, while the topic is still debated, some historians believe that Kennedy enflamed the Cold War. He increased the number of American advisors sent to Vietnam, which would become a full-fledged war under his successor, Lyndon B. Johnson. He also brought the world to the brink of a nuclear showdown during the Cuban Missile Crisis in 1962 and mounted a failed operation to topple Fidel Castro during the Bay of Pigs operation in 1961.
Domestically, he supported a progressive set of policies he called the New Frontier. Though long on idealism, few of his policies became a reality. However, he did start the Peace Corps, and he supported the Civil Rights movement and rights for people, like his sister Rosemary, who had intellectual disabilities. Many of his policies and programs would have to wait until after his death to become realities.
Kennedy's assassination in 1963 made him a martyr, and Americans are still obsessed with the death of such a young and vibrant leader. Many people felt that his death marked the end of an era of optimism, as the concluding years of the 1960s ushered in the Vietnam War and a great deal of domestic and international conflict.