Mary Jo Kopechne was killed in the auto accident that nearly ended Edward Kennedy's political career. Kopechne was a former campaign worker for Kennedy's brother, Robert F. Kennedy (who was assassinated during the 1968 presidential campaign). On 18 July 1969, Kopechne attended a party on Chappaquiddick Island, a short ferry ride off the island of Martha's Vineyard in Massachusetts. Edward Kennedy and Kopechne left the party together later that night; a short time later, their car plunged off the Dike Bridge into a pond, where it overturned. Kopechne died in the car. Kennedy swam ashore but didn't report the accident until the next morning, later claiming he had been dazed by the crash. The details of the incident have never been entirely clear, and Kennedy's critics suggested he had been driving drunk, had panicked after the accident, or even had tried to arrange a coverup of his involvement. Nothing was ever proved. Kennedy had been considered a likely candidate for president in 1972; instead he pled guilty to leaving the scene of an accident and had his driver's license revoked for a year.

Extra credit: Books about the incident include Jack Olsen's The Bridge at Chappaquiddick (1969) and Leo Damore's Senatorial Privilege (1988)... Kopechne's death was overshadowed in national news by the Apollo 11 moon mission, which had launched on 17 July and which culminated in Neil Armstrong's moon walk on 20 July... Edward Kennedy finally ran for president in 1980, but lost the Democratic nomination to incumbent Jimmy Carter, who then lost in the general election to Ronald Reagan... 30 years after the incident at Chappaquiddick, Kennedy's nephew John F. Kennedy, Jr. was killed in a private plane crash in the ocean off Martha's Vineyard... The bridge at Chappaquiddick is sometimes called Dike Bridge or Dike Road Bridge. It was closed to cars in 1981 due to disrepair. The bridge was rebuilt and reopened to traffic in 1996.