Are those the Ghosts of Kennedys Past and Present hovering over the New Hampshire primary? The coolly brilliant Barack Obama looks like a young Jack Kennedy, with the telegenic family reinforcing the image. Whereas Hillary Clinton seems more and more like Ted Kennedy — a relic of the past, a perpetual senator.

“Oswald’s Ghost,” a haunting new documentary by Robert Stone airing on PBS’ “American Experience” at 9 p.m. Jan. 14 (Thirteen/WNET locally) reminds us just how much we remain in the Camelot thrall. The film revisits the assassination of President John F. Kennedy by Lee Harvey Oswald (center below) on Nov. 22, 1963 in Dallas’ Dealey Plaza and especially, the conspiracy theories that mushroomed in the aftermath of the tragedy. Its cast of players — including historian Robert Dallek, reporter Dan Rather, novelist/essayist Norman Mailer and activist Tom Hayden — will be mostly old acquaintances to those who have charted this course before. It is to Stone’s credit that a familiar journey takes some unexpected turns.

Partly this has to do with Stone’s skill as a filmmaker, which gives the narrative a Hitchcockian flavor. (I particularly love the way the conspiracy theorists’ books swirl into a black hole, reminiscent of a silhouetted James Stewart falling during the dream sequence in Alfred Hitchcock’s “Vertigo.”) The score by Gary Lionelli — who collaborated with Stone on “Guerrilla” for “American Experience”— adds a particular urgency.

That urgency frames some arresting imagery. Though I remember watching the aftermath of the Kennedy assassination on TV when I was a child — including Oswald’s murder by nightclub owner Jack Ruby while still in police custody and Kennedy’s Lincolnesque funeral — I don’t recall hearing Oswald speak before (“I’m just a patsy”) or seeing him dead in the ambulence, his bruised face looking oddly at peace. It’s also the first time I’ve seen a still of Kennedy in the morgue — his face wearing a startled cast, his head carefully put back together.

The sounds and images remind us that while children were less shielded from horror years ago that was in part because access to some information was far more limited. There was no YouTube. Today, we are more mindful of what children watch — and parents might want to exercise some caution here — perhaps because information is ubiquitous and unrelenting. Like the Furies.

Stone isn’t trying to shock us, though. Rather, his theme is the conspiracy theory and how it blossoms and multiplies in a landscape of timely mistrust, which was the Vietnam era, and timeless incredulity.

“How could someone as inconsequential as Lee Harvey Oswald have killed someone as consequential as John F. Kennedy?” historian Robert Dallek wonders aloud. It’s easier to think that the Russians/Cubans/Vietnamese/Mafia/President Lyndon B. Johnson/CIA was/were behind it — take your pick of any or all — because if Oswald acted alone, then it is possible that the world is a randomly violent, violently random place — a chilling prospect.

After exploring the main conspiracy theories, however, that’s precisely what “Oswald’s Ghost” concludes. It expands the portrait of Oswald as a slight man of monstrous ego.

“He thought he was more than he was,” historian Priscilla Johnson McMillan observes. “He sought to identify himself with something big.”

The conventional wisdom — which I certainly bought into — is that Oswald lacked the brains and talent for the large gesture on the world stage. That’s why both the U.S. Marines and the Soviets got rid of him. But “Oswald’s Ghost” suggests that he was clever enough to wriggle out of the military and the old Soviet Union when neither suited his purpose any longer.

Our guide here is former conspiracy theorist Norman Mailer, who, as one critic put it, is the Virgil to our Dante as we wind our way through this particular Inferno. Mailer died on Nov. 10, so this must’ve been one of his last projects. As with his fascinating new book, “On God,” it turns out to be quite a swan song.

Like the insightful detective who unravels the crime in the last act, Mailer gets the final word in this nonfiction thriller, exhorting us to let common sense trump fear and daring us to think that what we thought might be true was really the other way around all along.