Lyndon Baines Johnson (often referred to as LBJ), was the thirty-sixth President of the United States (1963–1969). Johnson served a long career in the U.S. Congress, and in 1960 was selected by then-Presidential candidate John F. Kennedy to be his running-mate. Johnson became the thirty-seventh Vice President, and in 1963, he succeeded to the presidency following Kennedy's assassination. He was a major leader of the Democratic Party and as President was responsible for designing the Great Society, comprising liberal legislation including civil rights laws, Medicare (health care for the elderly), Medicaid (health care for the poor), aid to education, and a "War on Poverty." Simultaneously, he escalated the American involvement in the Vietnam War, from 16,000 American soldiers in 1963 to 550,000 in early 1968.