The Constitution says, “This Constitution, and the Laws of the United States which shall be made in pursuance thereof; and all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land”
However, this clause also provides a fairly obvious hierarchy of authority: Constitution, federal laws, treaties. Thus a treaty simply cannot override the Constitution. As the Supreme Court has ruled many times.
Not constitutionally, that is. Lord knows what some group will attempt to do.
I know what Obama and Lynch will do - just like Holder - ignore the Constitution.
End of problem.