I was vageuly aware of this story, just one in dozens of tales of tragedy in the Kennedy clan, but didn't know the ins and outs of it all.

Ted (Jason Clarke) is already feeling the pressure of his family's legacy after both Jack and Bobby have been assassinated, but amid his rise through the political firmament he has the time to go home to the Cape Cod area and enjoy a sailing boat race with his friends and close associates, including the young women who worked on Bobby's presidential campaign.

Later they all gather for a party in a nearby cabin, and Ted offers to drive one of the girls, Mary Jo (Kate Mara) home. Whether it's the loss of the boat race or frustration at trying to come out from his brothers' shadows (as well as lowered inhibitions after a night of partying), Ted drives recklessly, and after being seen by a local cop, he speeds off, mounts a small road bridge too fast, clips the egde and sends the car careening over onto its roof in the water, trapping he and Mary Jo inside.

To the end of his life Kennedy asserted that he tried to pull the young woman free, but his later testimony proved he was confused and didn't really know how he even got out. The film itself shows the incident in a series of flashbacks that don't really explain the sequence of events, but Ted finds himself sopping wet on the back of the pond, Mary Jo still trapped or maybe already dead inside.

But the real decision that proved fatal was Ted's failure to formally report the accident until well into the next day. Even with the local DA (Jim Gaffigan) and Ted's cousin and political advisor Joe (Ed Helms) urging him to do the right thing and trying to provide cover for the incident, Kennedy was either too concerned with how it would affect his standing or just wasn't in his right mind.

Even when a local man and his son find the car and a police diver is called and retriecs Mary Jo's body, Kennedy has barely started the official motions of reporting the crash.

But when the cruel and patrician father of the Kennedy clan, Joseph (Bruce Dern) appoints a team of spin doctors, lawyers and publicity experts, they close ranks around Kennedy, trying to help him manage the incident both legally and in the court of public opinion before he does any more damage.

It's very well crafted in every respect, telling a straightforward and prestige story, and if you're at all interested in the incident it's probably as definitive an account of how Ted Kenndy's presidential aspirations were derailed by a single stupid decision during a night of drinking and partying as you could ask for.