Social policy often does more harm than good, says one of the last of the original neocons.The Obama administration is entering a field not cultivated on a major scale since the 1960s: social policy. Unlike safety-net entitlements, such as health insurance and cash welfare, social policy—or social engineering, to use the more critical term—uses government action to try to change and improve people and their neighborhoods. For instance, the Obama administration’s Promise Neighborhoods are supposed to replicate, in 21 cities, what the Harlem Children’s Zone has done in Manhattan—to “create plans to provide cradle-to-career services that improve the educational achievement...