zook, where you had the statute of california that prohibited somebody operating as an interstate carrier without the icc license. it was raised -- well, you know, you have to let just the feds enforce that law. otherwise, there's the possibility of duplicative punishment, duplicative prosecution. and this court rejected that argument there. >> mr. clement, it seems that the -- i would think the largest hurdle for you is hines, which said the registration scheme -- congress enacted a complete registration scheme which the states cannot complement or impose even auxiliary regulations. so i don't see the alien registration as a question of obstacle preemption, but appeal preemption that alien -- we don't want competing registration schemes. we want the registration scheme to be wholly federal. >> well, justice ginsburg, i think that's part of the reason why i accepted justice kennedy's characterization of the relevant language in hines, because although there's some general discussion there of field preemption, when the court actually states what its holding is, it does state it in terms of

zook, where you had the statute of california that prohibited somebody operating as an interstate carrier icc license. it was raised -- well, you know, you have to let just the feds enforce that law. therwise, there's possibility of duplicative punishment, duplicative prosecution. and this court rejected that argument there. >> mr. clement, it seems that the -- i would think the largest hurdle for you is hines, which said the registration scheme -- congress enacted a complete registration scheme which the states cannot complement or impose even auxiliary regulations. so i don't see the alien registration as a question of obstacle preemption, but appeal preemption that alien -- we don't want competing registration schemes. we want the registration scheme to be wholly federal. >> well, justice ginsburg, i think that's part of the reason why i accepted justice kennedy's characterization of the relevant language in hines, because although there's some general discussion there of field preemption, when the court actually states what its holding is, it does state it in terms of obstacle preempt