White supremacist groups have been on the decline in the Midwest lately, with key leaders jailed or stepping down and membership in disarray. But experts warn the hate movement could actually become more violent under those circumstances, as angry "lone wolf" extremists take matters into their own hands. It's a theory that might be tested soon in Chicago, as authorities probe last week's execution-style shootings of the husband and mother of federal Judge Joan H. Lefkow. Lefkow came home on Monday to find the bodies of her husband, Michael F. Lefkow, 64, and her mother, Donna G. Humphrey, 89, in...