FEW events in recent U.S. policy history have had the resonance of the 1972 demolition of the Pruitt-Igoe housing project in St. Louis. By tearing down the 33 11-story buildings, once home to 10,000 residents, the government acknowledged, perhaps for the first time, that an important social program could go seriously awry; soon afterwards, Pruitt-Igoe entered policy discussion as an event and a metaphor.