Step-by-step explanation:
Senatorial courtesy is a long-standing unwritten, unofficial, and nonbinding political custom (or constitutional convention) in the United States describing the tendency of U.S. senators to support a Senate colleague when opposing the appointment to federal office of a nominee from that Senator's state.
The core message of the Supremacy Clause is simple: the Constitution and federal laws (of the types listed in the first part of the Clause) take priority over any conflicting rules of state law. The Supremacy Clause also establishes a noteworthy principle about treaties.