How the U.S. Fights the Zeta Cartel, From Spies to Sanctions

The Zetas are arguably Mexico's most powerful, most vicious drug cartel. And they're about to get nastier: the new kingpin is a brutal assassin who favors cooking his enemies inside burning oil drums. In ways both subtle and not, the U.S. government is trying to defang the cartel. Here's what we know about this quiet, billion-dollar campaign.