LIKE pious Muslims making the pilgrimage to Mecca, policy wonks have been flocking to Milwaukee to study its ambitious experiment in welfare reform. The reason why isn’t hard to figure out. Since 1987, Wisconsin’s welfare rolls have plummeted a stunning 88 percent; in Milwaukee, the state’s largest city, the welfare caseload has fallen 75 percent, far bigger than the average drop of other large cities. “Wisconsin Works,” or W-2, is the pinnacle of Wisconsin governor Tommy Thompson’s reform efforts.  Launched in 1997, W-2 has won praise from conservatives for its hard-nosed “work-first” principles and from liberals for its generous benefits. W-2’s ultimate success, though, will depend on what happens in Milwaukee, since over 80 percent of Wisconsin’s remaining welfare caseload—made up of the hardest cases—resides in that city. Milwaukee’s experience will demonstrate whether W-2 can serve as a model for all cities or works only for the easier-to-employ.