If you could settle the question with a national vote, there would be no doubt that a conspiracy killed John F. Kennedy. Two weeks after the shooting, a Gallup poll showed 52 percent of Americans blaming a force larger than Lee Harvey Oswald for the president's death. Half a century later, a new Gallup poll puts the number at 61 percent. Earlier this year an Associated Press survey said the number was 59 percent, while a Public Policy Polling effort said it was a more modest but still substantial 51 percent—not far at all from those initial results in 1963.
Those numbers may sound surprisingly high, but by other years' standards they're actually low. A decade ago, an ABC News poll had 70 percent of the population believing there was more than one man behind the slaying. When ABC posed the same question in 1983, the number was 80 percent. In 1994, the sociologist Ted Goertzel suggested that belief in a Kennedy conspiracy has "increased as the event became more distant." For a while it did, but then it reached a peak and started sinking.
So there are two trends that cry out to be explained here. Why are Kennedy assassination theories still so popular, and why are they less popular than before?
The simplest answer would go something like this: People rejected the lone-nut theory because they were persuaded by its critics, and then they started shifting away from the conspiracy stories when they re-evaluated the evidence. But plenty of high-profile crimes have left loose threads and open questions without attracting such intense doubt. And while some high-profile arguments against the conspiracy theories have appeared in the past couple of decades, notably Gerald Posner's book Case Closed and Vincent Bugliosi's Reclaiming History, it is far from clear that their arguments have reached a large portion of the population, let alone convinced them.
Something more is at work here, something larger than the evidence that Kennedy was or wasn't killed by a conspiracy. And that something is the mark his death left on the country's psychic landscape, a scar so deep that millions of people feel the need to look for that evidence in the first place. Other events that provoke conspiracy theories usually fade away. (Only a niche concerns itself with whether Arthur Bremer acted alone when he tried to kill Alabama Governor George Wallace.) Kennedy, by contrast, keeps commanding America's attention. And that reflects something more than the death of a President.