The California prison guards' union will take the state to court Friday, trying to stop inmates from being shipped to prisons in other states.
The transfers are part of Gov. Arnold Schwarzenegger's plan to deal with severe overcrowding. Some prisoners have volunteered to move.
But soon, the transfers will be involuntary. California's prisons are so overcrowded they're in danger of being taken over by the federal court.
Critics say the relocations won't solve the problem — and that they may be illegal.