Ted Kennedy was a U.S. senator.
The Chappaquiddick incident was a single-vehicle car accident on Chappaquiddick Island , Massachusetts on July 18 , 1969 that was the result of U.S. Senator Ted Kennedy 's negligence and resulted in the death of his 28-year-old companion , Mary Jo Kopechne , who was trapped inside the vehicle . Ted Kennedy . A member of the Democratic Party , he was the second most senior member of the Senate when he died and was the fourth-longest-serving senator in United States history , having served there for almost 47 years . In May 2008 , Kennedy was hospitalized after suffering a seizure and was diagnosed with a malignant brain tumor , which limited his appearances in the Senate .