Kennedy assassination documentaries have become as common an annual occurrence as the holiday specials that traditionally air a few weeks later. Discovery creates a kind of pincer action this time around, coming at the "Who shot JFK?" mystique from two diametrically opposed angles. Neither is wholly convincing, but the former has the more salacious title in mostly embracing a vast conspiracy, while the latter generally debunks part of what preceded it. The back-to-back hours are interesting, perhaps, but taken together, less substantial than a cool autumn breeze.

"Did the Mob Kill JFK?" relies primarily on the testimony of author Lamar Waldron and a jailhouse informant who claims that mobster Carlos Marcello boasted that organized crime had orchestrated President Kennedy's murder. The reason: Because the CIA had been working with the mob to try and assassinate Fidel Castro, with the mob participating in the hopes of getting their casinos in Cuba reopened. (As homework, just go watch "The Godfather, Part II" again.)...

... By contrast, "JFK: The Ruby Connection" meticulously (indeed, almost arduously) lays out events leading up to Ruby's televised murder of Oswald and basically accepts that Ruby acted alone out of anger over the assassination. For the "CSI" crowd, the project replicates the shooting from so many angles that Oswald gets riddled with more bullets than Bonnie and Clyde.

The latter hour is more refreshing, if only in that it knocks down popular conspiracy theories -- as producer Erik Nelson did in his 2008 spec on the topic, "JFK: Inside the Target Car," which employed high-tech wizardry to demonstrate -- sorry, Oliver Stone -- that Oswald could indeed have fired the fatal shot and thus been the lone gunman.