Yet another lessen in the futility of drug prohibition: Drug smugglers in Colombia have a low-cost way to transport cocaine -- narco-submarines. Authorities are struggling to keep up, and the technology keeps improving. Jay Bergman, who heads the Drug Enforcement Administration's Andean division, said it's a whole new challenge. "Without question, it has us all going back to the textbooks and the drawing boards and figuring out what are we going to do about this." Bergman pointed out that so far, no drug submarines have been detected under the sea. But seizures of semi-submersibles have dropped dramatically in the past two years. That could mean that traffickers have already made the switch to submarines – and that they're eluding detection.