By Rajesh Mirchandani
BBC News, Los Angeles
**California Governor Arnold Schwarzenegger has just hours in which to submit proposals to reduce the state’s prison population by 40,000.**If he fails meet a midnight (0700GMT)deadline set by federal judges, he could be held in contempt of court.
The judges had earlier ruled that inmates were housed in dangerously overcrowded conditions.
But state leaders recently rejected plans for the early release of thousands of prisoners.
California has 150,000 people behind bars, in prisons built for barely half that.
It is costly and - according to a federal court ruling - a health hazard for inmates.
Possible showdown
A panel of judges ordered a cut of 40,000 prisoners and set a deadline for plans on how to do it.
Mr Schwarzenegger recently tried to reduce the prison population to save more than a billion dollars for a cash-strapped state.
His ideas might also have satisfied the court.
But state lawmakers refused, saying dangerous criminals would be let loose.
Early release is also likely to be unpopular with voters.
Now it means the governor could be held in contempt of court if he fails to submit appropriate plans within the time limit.
Technically that means he and other leaders could be locked up, though such a move is unlikely.
What is possible is that state proposals will deliberately fall short in order to force a showdown at the highest level - the US Supreme Court.
California may argue that federal judges should not interfere in state prison policy.