1. 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 in opposing the appointment to federal office of a presidential nominee from that Senator's state.
2. Appointment to Judicial Branch. ... The appointment process serves as a check and balance on the judicial branch because the members of the other two branches select the members of the judicial branch. They choose the Supreme Court justicesand all federal court judges.