The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.applies to the people as well. Who knew?
Well, the Supreme Court ruled once and the case is back in front of them again.
The argument at hand? That Congress cannot expand its enumerated powers by agreeing to a treaty. The government is arguing that they have the right to prosecute an individual under the terms of an international treaty, the plaintiff argues that there is no justification in the Constitution for her crime being a federal crime.
Another example of the federalization of crime, a direction never intended by the drafters or adopters of the Constitution, but in this case, there may be enough justices on the Supreme Court who realize that Congress is overstepping their bounds and that it is time to curtail them, even if just a little.