IF a neoconservative is a liberal mugged by reality, then Heather Mac Donald may be the most neoconservative person alive, given the many muggings she has put herself through in the last five years. From inner-city schools to law schools, from foundations to museums, from public health centers to homeless shelters, Mac Donald has done her own one-woman run through the institutions. Her many essays in City Journal, now collected in The Burden of Bad Ideas, tell a story of “compassion gone mad,” a parable of how the “destructive and blinding ideas” of intellectuals and activists have wreaked havoc on America’s cities and culture and on the lives of the urban poor.