On July 18, 1969, Senator Edward Kennedy drove off a bridge on Chappaquiddick Island. The Massachusetts Democrat, 37, survived the plunge, but his companion Mary Jo Kopechne, 28, perished in the submerged car, and Kennedy waited 10 hours to report the accident. He then deployed a squad of sycophants to handle the cops, the court, the coroner and the press. And the senator got off with a tap on the wrist.

Nearly 50 years later, the Entertainment Studios film Chappaquiddick does a decent job conveying those basic facts, with a particularly strong performance from Jason Clarke as Ted Kennedy. With other key facts and situations, on the other hand, the film treads far too softly.

As in years past, in 1969 the party for the Kennedys’ “boiler room girls” was a wild bash. In movie rendition, however, the party is so tame viewers might expect Franky Avalon and Annette Funicello, and in similar style there’s nary a navel in sight.

Kennedy and Kopechne (Kate Mara) were both drunk, and they didn’t go for a drive to discuss campaign strategy. Spooked by a cop, Kennedy roars off at high velocity and promptly drives off a bridge into Poucha Pond. One of his first thoughts is, “I am not going to be president”—an office he evidently thought was family property. As his handlers explain, that won’t happen if he is indicted for involuntary manslaughter, which the case clearly involved.

Chappaquiddick does best at showing Kennedy’s team leaping into action, with Clancy Brown as Robert McNamara and Taylor Nichols playing Kennedy scribe Ted Sorensen.

The film neglects to note that even senators such as Mike Mansfield (D-Mont.) weighed in on Kennedy’s behalf. Also overlooked was an “urgent” message from the FBI’s Boston office, noting that “a body of a female” was found in the overturned car and that “Stated fact Senator Kennedy was driver is not being revealed to anyone.”

Kennedy was planning to say Mary Jo was driving, but eventually he fesses up. Viewers don’t hear from diver John Farrar, but they may surmise that, had Kennedy reported the incident immediately, Mary Jo’s life could have been saved.

Viewers should cross-check the details with Senatorial Privilege: The Chappaquiddick Cover-Up by Leo Damore, who covered the incident as a reporter for the Cape Cod News. A key source for the book is Joe Gargan, Ted Kennedy’s cousin, who grew weary of covering for the senator.

In Chappaquiddick, Ed Helms plays Joe Gargan and Bruce Dern has a go at patriarch Joe Kennedy. He tells son Ted, “you will never be great,” but at the end the film explains that Ted went on to become the “lion of the Senate.” So the obvious takeaway is that the loathsome drunk who left Mary Jo to die eventually became a great man. For their part, viewers may wonder if this was Ted’s greatest lapse.

In 1984, Senator Edward Kennedy sought help from the Soviet Union, then headed by the KGB’s Yuri Andropov, an old-line Stalinist. Kennedy offered to lend Andropov a hand in dealing with President Reagan. In return, the Soviet boss would help the Democratic Party to challenge Reagan in the 1984 presidential election.

The gambit failed, and Reagan won in a landslide over both the Democrats’ Walter Mondale and Geraldine Ferraro and Communist Party USA candidates Gus Hall and Angela Davis. That was the pair the Russians wanted to win.

Kennedy’s covert caper would make a great movie, perhaps with Jason Clarke again as the star. If Chappaquiddick is any indication, the film won’t be appearing any time soon.