An unwritten tradition whereby nominations for state-level federal judicial posts are usually not confirmed if they are opposed by a senator of the president's party from the state in which the nominee will serve is called

Senatorial Courtesy.

Explanation:

Based on the information provided within the question it can be said that the term being described is called Senatorial Courtesy. This (like mentioned int he question) is a political custom that describes the tendency that U.S. senators have in voting with other Senate colleagues in order to go against a presidential nominee. Which is what is described in the question.

If you have any more questions feel free to ask away at

acid rain is the answer

answer; i believe the correct answer is (4) flip a coin as each participant arrives,heads indicates assignment to the first group: tails indicates assignment to the second group;