The Robert F. Kennedy presidential campaign began on March 16, 1968, when Robert Francis Kennedy, a United States Senator from New York, mounted an unlikely challenge to incumbent Democratic United States President Lyndon B. Johnson. Following an upset in the New Hampshire primary, Johnson announced on March 31 that he would not seek re-election. Kennedy still faced two rival candidates for the Democratic Party's presidential nomination: the leading challenger United States Senator Eugene McCarthy and Vice President Hubert Humphrey. Humphrey had entered the race after Johnson's withdrawal, but Kennedy and McCarthy remained the main challengers to the policies of the Johnson administration. During the spring of 1968, Kennedy led a leading campaign in presidential primary elections throughout the United States. Kennedy's campaign was especially active in Indiana, Nebraska, Oregon, South Dakota, California, and Washington, D.C. After declaring victory in the California primary on June 4, 1968, Kennedy was assassinated at the Ambassador Hotel in Los Angeles. He died on June 6, 1968 at Good Samaritan Hospital. Had Kennedy been elected president, he would have been the first brother of a former U.S. president to win the presidency himself.

Robert Francis Kennedy, also known by his initials RFK, was an American politician and lawyer. He served as the 64th United States attorney general from January 1961 to September 1964, and as a U.S. senator from New York from January 1965 until his assassination in June 1968, when he was running for the Democratic presidential nomination. Like his brothers John F. Kennedy and Ted Kennedy, he was a prominent member of the Democratic Party and is an icon of modern American liberalism.