the unwritten rule of senatorial courtesy applies to what appointments
Senatorial courtesy 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.[1] The practice is motivated by a general sense of collegiality among Senators and the assumption that a Senate colleague will have the best first-hand knowledge of the personal character and qualifications of nominees from his or her own state. It is also viewed as an "important source of political patronage"[2] for U.S. senators.
Filibuster in the United States Senate A filibuster in the United States Senate is a dilatory or obstructive tactic used in the United States Senate to prevent a measure from being brought to a vote. The most common form of filibuster occurs when one or more senators attempts to delay or block a vote on a bill by extending debate on the measure. The Senate rules permit a senator, or a series of senators, to speak for as long as they wish, and on any topic they choose, unless "three-fifths of the Senators duly chosen and sworn"[1] (usually 60 out of 100) bring the debate to a close by invoking cloture under Senate Rule XXII.