The latest example of Washington's disturbing tendency to do Mexico's bidding concerns the popular bounty hunter Duane "Dog" Chapman, whom U.S. marshals arrested last month. Mr. Chapman's crime? In June 2003, he apprehended Andrew Luster in Puerto Vallarta, Mexico, where the convicted rapist had fled some five months earlier. Because of Mr. Chapman, Luster is now serving his 124-year sentence in California. We think this makes Mr. Chapman a hero; but the Mexican government says he's a criminal. Bounty hunting is illegal in Mexico. So, when Mr. Chapman brought Luster into custody in Mexico he too was detained. But after...