Can a defendant who has been adjudged incompetent be kept in a federal prison indefinitely?

No, a defendant who has been adjudged incompetent cannot be held indefinitely in a federal prison. Under U.S. law, individuals found incompetent to stand trial must be evaluated periodically, and if they do not regain competency, they may be subject to civil commitment procedures rather than criminal detention. Furthermore, the Supreme Court has established that indefinite detention without a chance of trial is unconstitutional. The focus is on treatment and rehabilitation to restore competency, not punishment.