A federal disctirct judge is the official judicial officer that presides over federal criminal and civil trials. District court judges are appointed by the President and confirmed by the Senate in accordance with Article III of the United States Constitution.
District court judges have lifetime appointments and do not have to be reappointed or run for reelection; their salary cannot be reduced once in office. These measures were intended to insulate district judges from political pressures. District court judges do not answer to anyone; however, decisions by district court judges can be appealed to circuit courts of appeal and ultimately the United States Supreme Court.
Assisting the district court judges are magistrate judges. Magistrate judges handle the initial court appearances in felony cases and are authorized to adjudicate misdemeanor and petty offenses. The first appearances (arraignment, bail, preliminary examination) in a felony, for example, will most likely be presided by a judicial magistrate.