It may well be that the racial attitudes and beliefs held by white landlords and realtors in early twentieth-century Harlem were more hostile to blacks than the attitudes and beliefs of white residents and officials in late twentieth-century San Francisco. But, in terms of end results, the actions of the former failed to keep blacks out of Harlem, while the actions of the latter drove out of San Francisco more than half the blacks already living in that city. Costs matter.
