The judicial foundation for the law of federal supremacy can be traced to two opinions by Chief Justice John Marshall, McCulloch v. Maryland, 17 U.S. (4 Wheat.) 316 (1819), and Gibbons v. Ogden, 22 U.S. (9 Wheat.) 1 (1824). While neither opinion breaks ground beyond that which should be evident from the text of the Supremacy Clause, both opinions affirm, with confident and enduring rhetoric, the principle of federal supremacy within the sphere of constitutionally granted federal powers. The essence of that principle is that no state may transgress the norms of the Constitution or interfere with the constitutional exercise of federal authority.