Article VI, Section 2:
"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; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding."
I thought you knew the USC...
“The true barriers of our liberty are our State governments; and
the wisest conservative power ever contrived by man, is that of
which our Revolution and present government found us possessed.”
—Thomas Jefferson to A. L. C. Destutt de Tracy, 1811.