...exposes Nixon's role as the liaison between the CIA and the Mafia in their failed plots to assassinate Cuban revolutionary Fidel Castro...
The CIA had been paying the mob as one of the avenues for snuffing Castro. The mob came to the conclusion, early on, that it was a futile effort. The Kennedy brothers (not Ted, he was already displaying his utter uselessness somewhere) ordered that part of the program terminated, reasoning that, even if successful, the US gov't would be exposed as having paid tax dollars to the mob. They already owed JFK's election to mob chicanery, and were in the process of turning on them.
Turns out that the CIA didn't terminate the program, and the mob kept taking the money. When the mob later murdered both Kennedy brothers, they used the threat of exposing the CIA payments to ensure the silence of the CIA, and it worked perfectly. Helms denied to Congress knowing the trigger man when shown photos of him. Nixon enjoyed payoffs from the mob, because he knew the whole story, and the mob knew he knew it, and paid him off for silence.
Nixon wound up associated with Frank Sturgis -- and a simple web search should turn up the photo of Sturgis, in Cuba, holding a rifle, with which he'd recently gunned down a group of Batistiano captives, and the scene of the photo is Frank standing on their fresh mass grave. Castro had taunted and threatened Sturgis, claiming he couldn't be trusted, being an American, so Sturgis did as Castro ordered (mass-murder Batistianos) to prove he was trustworthy. Sturgis could have pulled the trigger on Castro any time, but decided he didn't stand to actually get the contract money, since he wouldn't have survived the escapade (even if he had been successful).
Funny how Nixon's political career came to a sudden end though, huh? Kennedy bangs thousands of women during his marriage, in competition with his brother Bobby who did the same, and alleged journalists saw this going on in the White House, and said nothing. Diem assassinated, hey, it's somebody else's doing! JFK takes the world to the brink of nuclear war not once but twice, no problem, not even in retrospect.
And by the way, WTF is HuffPo "reporting" doing creeping onto and stinking up FR?