A poll found 75% fear a U.S. invasion motivated by desire for natural riches. BELÉM, Brazil - Afghanistan was the first to fall. Iraq, with all that oil, was next. And Socorro Leite says she has a fair idea of what else lies in the sights of the Americans. "Soon," she warns, "their target will be the Amazon." Insidious plots are afoot to snatch the rain forest from Brazil and declare it an international protectorate, the 45-year-old political aide believes. Foreign scientists and environmental activists are secret fronts for nations bent on laying claim to the region's abundant riches. American...