If the treaty violates some provision of the Constitution, sure.
They can rule BEFORE hand that some provision doesn't fly perhaps, but if they did so after the fact, I would think that the treaty would be null & void, etc.
If that is the case, I need to let my accountant know NOT to pay my taxes to the Feds this year, but rather to the State of Texas, (or Republic of Texas perhaps :)
that's WHY you have to be so VERY careful about what language is in them.
free dixie,sw