Final answer:
Federal judges are nominated by the President and confirmed by the Senate, holding lifetime terms, while state judges are often elected and serve fixed terms.
Step-by-step explanation:
The major difference between the selection of federal judges and most state judges lies in the appointment and confirmation process versus elections. Federal judges, including those on the U.S. Supreme Court, are nominated by the President and must be confirmed by a majority vote in the U.S. Senate. This is a function of the Senate's "advice and consent" role. In contrast, state judges are often elected by the public or appointed through various methods depending on the state. Another key difference is the term length; federal judges are appointed for lifetime tenure, which is intended to ensure their independence from political pressures. This contrasts with most state judges who have fixed-term lengths or are subjected to re-election.