Does state law or federal law have the final power?

Answer 1

The short answer is that the United States Constitution is the law of the land, and any law, including state law, that is not consistent with the US Constitution is superseded by the US Constitution.

There is something called the Supremacy Clause, which means that all inconsistencies between federal and state law must be resolved in favor of federal law, but then the lawyers and courts argue whether the federal law in question was intended to supersede and preempt, or to just add to state law. Is the state law really and truly inconsistent, or just a little. :)

If state law says you can manufacture WIDGET A, for example, and federal law says you cannot, then federal law will control, because that is a direct conflict. But if state law says you can manufacture Widget A, and federal law says you can manufacture Widgets A, B and C, but you must comply with certain requirements, or you must manufacture them all together but not individually, then state law is not superseded...it is just ... clarified a bit, if you get my meaning.

Answer 2

Not quite... federal law is federal law and is in addition to state law, except where there is a state and federal law that are virtually identical, in which case the federal law may "supersede" the state law -- this is the constitutional principle of federal "supremacy". On the other hand yes federal law applies in every state, but remains federal law. And do local law enforcement officials have the right to arrest and ticket you for violation of certain Federal Laws, yes.