The Supreme Court heard arguments recently in a challenge to California's policy of segregating inmates by race in their first 60 days of incarceration. Prison officials argue that the practice reduces racially motivated violence. But government-imposed racial segregation should be permitted only in extraordinary circumstances, if at all. The court should strike down the policy.

When inmates arrive at California Department of Corrections facilities, either as new inmates or transfers, they are temporarily held in double cells at a prison "reception center." When cell assignments are made, the inmates are divided into four general categories: black, white, Asian and other. Inmates are almost invariably assigned cellmates of their own race.

The State of California says its policy, by which hundreds of thousands of prisoners were segregated last year, reduces violence in the cells. After 60 days, the state says it has enough information to decide whether particular inmates are dangerous. Of course, it is possible that the policy makes things worse. At oral argument, Justice John Paul Stevens asked what he called a "stupid question": whether, if California wants to discourage racial gangs, it wouldn't make more sense to house prisoners with members of a different race.

The United States Court of Appeals for the Ninth Circuit upheld the policy. It invoked a Supreme Court precedent, Turner v. Safley, giving prisons broad authority in how they handle their inmates. California produced little evidence to support its segregation policy, but the court accepted as "common sense" the notion that there is a connection between segregating prisoners and combating violence.