By writing tough zoning ordinances, many of America's suburban towns and villages have curbed the construction of apartment buildings and required that each new house be built on a substantial plot of land. Zoning has thus had the effect often by intent of excluding low-and moderate-income families who cannot afford to buy or rent most available housing. It has also kept many towns lily-white.
That strategy will no longer work in one state. The New Jersey Supreme Court last week banned restrictive zoning throughout the state. The ruling resulted from a suit brought by the N.A.A.C.P., CORE and...