1) A lawyer needs to be admitted to the bar (or practice of law) in a state to represent someone there, so if the person is in state A, only a lawyer admitted to practice in state A can represent him--and it is unlikely that a public defender in B would be eligible to practice in state A.2) Even if the attorney is admitted to practice in a state, there is no realistic chance that state B (which pays for/provides public defenders) will pay for one of its lawyers to represent a defendant in another state (e.g. state A); state B would feel that state A should foot the bill and provide the attorney.