In the United States, within 100 years, four presidents—Abraham Lincoln, James A. Garfield, William McKinley and John F. Kennedy—died at the hands of assassins. There have been at least 20 known attempts on U.S. presidents' lives. Huey Long, a senator, was assassinated on September 10, 1935. Robert F. Kennedy, a senator and a presidential candidate, was also assassinated on June 6, 1968, in the United States.