NO ONE, except Sen. Kennedy himself has any idea of exactly what happened, and he said even he was not sure...

from the article linked above:

"... He insisted that he was "not driving under the influence of alcohol" nor had he "engaged in any immoral conduct" with Kopechne. "But my conduct and conversations during the next several hours (following the accident) to the extent that I can remember them make no sense to me at all," he added. "Although my doctors informed me that I suffered a cerebral concussion as well as shock, I do not seek to escape responsibility for my actions by placing the blame either on the physical, emotional trauma brought on by the accident or on anyone else. I regard as indefensible the fact that I did not report the accident to the police immediately."

For 40 years since, Ted Kennedy has been an exemplary public figure, working to make life better in every way he could. What more could be asked of someone, whether they had an 'unfortunate incident' in their past or not?

I despair at these attempts by those who do not know to judge and decide that someone's life is defined by what they assume about something 40 years ago.

Let's let him rest.