Final answer:
Federal and Supreme Court justices serve for life tenure upon appointment, ensuring an independent judiciary. Their appointments are made by the President and confirmed by the Senate.
Step-by-step explanation:
Federal and Supreme Court justices, once appointed by the President and confirmed by the Senate, serve for life tenure, barring impeachment or voluntary retirement. This life tenure is meant to ensure an independent judiciary free from undue political pressure, allowing them to rule on cases without fear of consequence for their decisions. The Supreme Court consists of one chief justice and eight associate justices, all of whom serve under the same condition of life tenure. The Michigan state court system, as a point of contrast, has elected judges serving fixed terms. The idea of an independent judiciary is central to the United States judicial system and is supported by Article III of the Constitution, which states that federal judges hold their office during "good Behavior," a term that has been interpreted to mean for life.