Yesterday the New Jersey State Assembly passed a bill, already approved by the state Senate, that allows judges to waive heretofore mandatory sentences for nonviolent drug offenses committed in "drug-free zones." Under state law, such zones include any place within 1,000 feet of a school or 500 feet of a park, library, museum, or public housing project. Selling drugs (or possessing them with intent to sell) within that area triggers a mandatory minimum sentence of three years. The bill abolishing that rule, which Gov. Jon S. Corzine has promised to sign, follows years of lobbying by critics who argue that drug-free zones, aimed mainly at shielding children from drug dealers, arbitrarily increase the punishment for disproportionally black and Hispanic defendants whose offenses have nothing to do with children. The zones are defined broadly enough to include most or all of many cities.