He swam free, leaving his 28-year-old companion and campaign assistant Mary Jo Kopechne trapped inside the vehicle in seven feet of water — where she drowned. The body of Kopechne was recovered the next day.
Kennedy did not report the incident to authorities for 10 hours and, in what later became known as the “Chappaquiddick Incident,” the resulting personal and political scandal made national headlines and derailed Kennedy’s presidential ambitions.
At 38, Kennedy was the youngest son of Joseph P. Kennedy, Sr., and Rose Kennedy. He was the youngest brother of former President John F. Kennedy and Senator Robert F. Kennedy, who were both assassinated.
His night started at a rented cottage on the island, which is located near Martha’s Vineyard, Massachusetts, where he and his cousin Joe Gargan had been hosting a cookout and party.
Kennedy, who was married, left the party at around 11 P.M. He later claimed the Dike Road excursion was a wrong turn, but the road he was driving down led to a secluded ocean beach just beyond the bridge. Mary Jo was in the backseat and, while he claimed he was just giving her a lift back to her hotel, it was widely believed that the couple were en route to a romantic tryst.
After the accident, Kennedy was able to break free from the car, and reportedly dove down and tried to retrieve Kopechne from the sunken Oldsmobile. He was not successful, so he went back to the cottage and got Gargan and another friend to help look for Kopechne. Once again, the three men could not locate the body.
So they went to the ferry slip, where Kennedy dove into the water and swam away. He later returned to his room at the Shiretown Inn, changed his clothes, and at around 2:25 A.M. told the innkeeper that he had been woken up by noise next door — and asked what time it was.
In Leo Damore’s Senatorial Privilege – The Chappaquiddick Cover-up (1988), the author alleges that Kennedy may have been trying to establish an alibi. He also recounts an interview with Joe Gargan in which Gargan claimed that Kennedy had plotted to make Kopechne the driver and sole occupant of the automobile.
At 9:45 A.M., Kennedy finally reported the incident to police, and admitted that he was the driver.
Divers later estimated that if he had called them immediately, they would have had time to pull out Mary Jo. She had not drowned immediately, but had survived in an air pocket inside the car — she was asphyxiated only when the oxygen ran out several hours later.
On July 25, Kennedy pleaded guilty to leaving the scene of an accident. He received a two-month suspended sentence and had his license suspended for a year. Many people believe that he used his family’s political influence to avoid a harsher sentence.
In a televised statement, Kennedy called the delayed reporting of the accident “indefensible,” but vehemently denied that he been involved in any improprieties with Kopechne. Regardless, the incident and its aftermath hindered his chances of ever becoming President. His only attempt, in the 1980 election, resulted in a loss to incumbent President Jimmy Carter, who later lost the election to Republican candidate Ronald Reagan.
But he continued to serve as U.S. senator from Massachusetts, and campaigned for causes including universal health care. In 2008, he was hospitalized after suffering a seizure and was diagnosed with a malignant brain tumor. He died on August 25, 2009, at his home in Hyannis Port, Massachusetts.