Ronald Reagan's defense secretary, Caspar Weinberger, credited with engineering the demise of the Soviet Union, once predicted – because of illegal immigration and social unrest south of the border – the U.S. would be at war with Mexico by 2003. As the U.S. becomes increasingly concerned about just those issues – and one more, the growing power and violence of the drug cartels operating in and around the border – some U.S. intelligence and military analysts are dusting off Weinberger's "Operation Aztec" battle plan for review. Weinberger's scenario outlined a rapid three-pronged military invasion designed to control domestic Mexican unrest...