Senator Edward "Ted" Kennedy had attended a reunion party of activists for his brother, Robert Kennedy's, terminated presidential campaign. (Ted Kennedy was Bobby's younger brother and had, following Bobby's assassination the previous year, been seen as his successor.)

It is reported that Kennedy left the party just after 11pm with Mary Jo Kopechne, 28, saying he intended to drive back to catch a ferry to their respective lodgings on Martha's Vineyard.

Kennedy turned the car onto Dike Road, which was unpaved, drove for a short while, then missed the ramp to a narrow wooden bridge and drove straight into Poucha Pond. Kennedy managed to get out of the submerged car, but Kopechne could not, despite his efforts to help free her.

If that wasn't bad enough, Kennedy's actions after the event have been the subject of much criticism and speculation.

One of the allegations was that Kennedy hadn't intended to go to the ferry at all, but that a terrible accident had occurred while he was having an affair - there are reports that the road he was driving down led to a secluded beach, and, also, that they had both been there, together, before.

(The story they were going to get a ferry back to their hotels is also a little suspicious when it was discovered that Kopechne left her purse and room key at the party.)

Back at the scene of the accident, Kennedy, after his own attempt to free Kopechne had failed, got help from two other men. But they could not recover the body. Kennedy then, apparently, dove into the water and swam to his lodgings in Edgartown, about a mile away. He got back to his room, changed his clothes, and then, at 2:25, it is said he asked the innkeeper what time it was. Was Kennedy thinking of trying to establish an alibi?

Whatever the reason for this inquiry, Kennedy, 10 hours after the event, reported the incident to police and admitted he was the driver. He was given a 2 month suspended sentence and had his driving license suspended for a year. There are allegations that he used his considerable political power to avoid a more serious charge.

At the time of this incident, Kennedy was a potential presidential candidate. This incident put an end to those ambitions. It was also dangerous for his entire political career. His constituents, however, were supportive, and to this day (June 2006) he is a senior figure in the Senate.