If marijuana is legalized, John Mica warned at a recent congressional hearing, there will be blood. "In the last dozen years," the Florida Republican said, "we've had [half] a million Americans slaughtered on the highways…and half of those fatalities are related to people who are impaired through alcohol or drugs." Legal pot will compound this "phenomenal devastation," he said, since "we are going to have a lot more people stoned on the highway."

Mica, a proud pot prohibitionist who chairs a subcommittee of the House Oversight and Government Reform Committee, convened the hearing to raise an alarm about the deadly threat that legalization poses to anyone navigating the roads and highways. But by the end of the hearing, says Jacob Sullum, anyone who was paying attention recognized that Mica's grim prophecies have little basis in fact.