"Madison is just the beginning!" AFL-CIO chief Richard Trumka told a union rally in Annapolis on Monday. "Like that old song goes, 'You ain't seen n-n-n-n-nothing yet!' " Fresh from defeat in Wisconsin, union leaders are planning a new campaign not just to head off future challenges to their collective bargaining powers but also to make the case that organized labor's benefits and prerogatives -- wages, health care, and pensions that are more generous than those of comparable workers in the private sector -- are the moral equivalent of rights won by black Americans