The Sargent Shriver National Center on Poverty Law’s complaint is on target, but it shouldn’t take federal intervention to curb this kind of aldermanic fiat. Aldermen ought to realize that blocking affordable housing in this way perpetuates segregation. If they need data, they can turn to a study earlier this year by the Chicago Area Fair Housing Alliance that found that aldermanic privilege was being used in largely white, affluent areas to keep out affordable housing. That practice effectively confines lower-income Latino and black residents to West and South side neighborhoods.