ant to the purposes of . . . commitment.???123 Thus, the in[p.1770]sanity acquittee may be confined for treatment ???until such time as he has regained his sanity or is no longer a danger to himself or society.???124 It follows, however, that a state may not indefinitely confine an insanity acquittee who is no longer mentally ill but who has an untreatable personality disorder that may lead to cri