<P> There have been six foreign - born justices in the Court's history: James Wilson (1789--1798), born in Caskardy, Scotland; James Iredell (1790--1799), born in Lewes, England; William Paterson (1793--1806), born in County Antrim, Ireland; David Brewer (1889--1910), born in Smyrna, Turkey; George Sutherland (1922--1939), born in Buckinghamshire, England; and Felix Frankfurter (1939--1962), born in Vienna, Austria . </P> <P> There are currently four living retired justices of the Supreme Court of the United States: John Paul Stevens, Sandra Day O'Connor, Anthony Kennedy, and David Souter . As retired justices, they no longer participate in the work of the Supreme Court, but may be designated for temporary assignments to sit on lower federal courts, usually the United States Courts of Appeals . Such assignments are formally made by the Chief Justice, on request of the chief judge of the lower court and with the consent of the retired justice . In recent years, Justice O'Connor has sat with several Courts of Appeals around the country, and Justice Souter has frequently sat on the First Circuit, the court of which he was briefly a member before joining the Supreme Court . </P> <P> The status of a retired justice is analogous to that of a circuit or district court judge who has taken senior status, and eligibility of a supreme court justice to assume retired status (rather than simply resign from the bench) is governed by the same age and service criteria . </P> <P> In recent times, justices tend to strategically plan their decisions to leave the bench with personal, institutional, ideological, partisan and sometimes even political factors playing a role . The fear of mental decline and death often motivates justices to step down . The desire to maximize the Court's strength and legitimacy through one retirement at a time, when the Court is in recess, and during non-presidential election years suggests a concern for institutional health . Finally, especially in recent decades, many justices have timed their departure to coincide with a philosophically compatible president holding office, to ensure that a like - minded successor would be appointed . </P>

How many supreme court justices must there be