SINCE the mid-1960’s, public discussion over racial integration in our public schools has increasingly become a debate over the costs, benefits, and justice of mandatory school busing. That this should be so is not surprising.  During this time it became apparent that the mere removal of legal barriers to racial integration in the schools had not produced the heterogeneity of school populations-especially in big cities-that integrationists had hoped for. And it became apparent as well that people were not about to move voluntarily from one neighborhood or community to another in a way that would make such heterogeneity more likely.