United States district judges
A judge of a United States district court is officially titled a "United States District Judge". Other federal judges, including circuit judges and Supreme Court Justices, can also sit in a district court upon assignment by the chief judge of the circuit or by the Chief Justice of the United States. The number of judges in each district court (and the structure of the judicial system generally) is set by Congress in the United States Code. The President appoints the federal judges for terms of good behavior (subject to the advice and consent of the Senate), so the nominees often share at least some of his or her convictions. In states represented by a senator of the President's party, the senator (or the more senior of them if both senators are of the president's party) has substantial input into the nominating process, and through a tradition known as senatorial courtesy can exercise an unofficial veto over a nominee unacceptable to the senator.
With the exception of the territorial courts (Guam, the Northern Mariana Islands, and the Virgin Islands), federal district judges are Article III judges appointed for life, and can be removed involuntarily only when they violate the standard of "good behavior". The sole method of involuntary removal of a judge is through impeachment by the United States House of Representatives followed by a trial in the United States Senate and a conviction by a two-thirds vote. Otherwise, a judge, even if convicted of a felony criminal offense by a jury, is entitled to hold office until retirement or death. In the history of the United States, only twelve judges have been impeached by the House, and only seven have been removed following conviction in the Senate. (For a table that includes the twelve impeached judges, see Impeachment in the United States.)
A judge who has reached the age of 65 (or has become disabled) may retire or elect to go on senior status and keep working. Such senior judges are not counted in the quota of active judges for the district and do only whatever work they are assigned by the chief judge of the district, but they keep their offices (called "chambers") and staff, and many of them work full-time. A federal judge is addressed in writing as "The Honorable John/Jane Doe" or "Hon. John/Jane Doe" and in speech as "Judge" or "Judge Doe" or, when presiding in court, "Your Honor".
District judges usually concentrate on managing their court's overall caseload, supervising trials, and writing opinions in response to important motions like the motion for summary judgment. Since the 1960s, routine tasks like resolving discovery disputes can, in the district judge's discretion, be referred to magistrate judges. Magistrate judges can also be requested to prepare reports and recommendations on contested matters for the district judge's consideration or, with the consent of all parties, to assume complete jurisdiction over a case including conducting the trial.
Federal magistrate judges are appointed by each district court pursuant to statute. They are appointed for an eight-year term and may be reappointed for additional eight-year terms. A magistrate judge may be removed "for incompetency, misconduct, neglect of duty, or physical or mental disability". A magistrate judgeship may be a stepping stone to a district judgeship nomination.
As of 2010, there were 678 authorized district court judgeships. A study put forth by Brennan Center for Justice at New York University of Law found that under the Obama administration and especially in the year 2009 there have been a "uniquely high" number of vacancies in Federal Court, averaging 60 or more from the years 2009 to 2013. The Obama administration has blamed Senate Republicans for opposing (and therefore, not confirming) presidential nominations, while the Republicans say Obama has been slow to nominate.