In most instances, federal trumps state . . .
The Constitution's Supremacy Clause makes it clear that any law passed by Congress trumps state law or constitution. Article IV, clause 2, specifically reads, "This Constitution, and the Laws of the United States which shall be made in Pursuance thereof ... shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding."
So, generally speaking, federal supersedes state. Federal statute is superseded by the US Constitution.
HOWEVER, the waters get muddied . . .
In May 2009, the U.S. Supreme Court refused to hear the landmark case brought by San Diego County, effectively negating any claim that federal law supersedes state law. See
this page for a very cursory overview. Google the topic if you're interested in the issue, it makes a good read and lively debate.
As for US statutes re: prostitution, there are very few and
there is NO federal statute specifically "outlawing" prostitution, as has been discussed previously in depth here on ECCIE and ASPD - see
http://prostitution.procon.org/view....ourceID=000119 and see section I.
The whole "Indian Reservation" issue is a legal nightmare that has been discussed since almost day one of granting the tribes sovereignty and territory . . . it will never be completely "put to rest" until it is tried (opened) and shut down (if it indeed is) and the US Supreme Court will most likely weigh in, and no tribe has pushed it that far, that I am aware of . . . yet. It has been brought to vote (the proposal to open a brothel on reservation land) at many tribal council meetings and consistently it is voted down each time. In Arizona, the Salt River Pima-Maricopa Indian Community has the issue raised at almost every meeting - it is always dismissed immediately.
In every OPINION, it should be perfectly legal, however, the US has statutes that prohibit their citizenry from crossing international boundaries to pay for sex (currently targeted at individuals that travel for sex that involves a minor in the country visited), and it is that statute that typically quashes the proposal as it (said statute) may be (will be, most likely) rapidly amended by Congress to cover non-tribal members that cross a tribal boundary to pay for sex - in fact, several legislators have threatened to strengthen the laws with that very wording if the tribes attempt to open a brothel on a reservation. With that consideration, it will most likely only ever be "legal" for a tribal member to pay for services on a reservation in a tribal controlled brothel staffed by tribal prostitutes, and non-tribal members would be subject to prosecution when they exited the reservation if they entered it and engaged the services of a prostitute on a reservation if such brothel did indeed exist.
Kisses,
- Jackie