level of some state supreme courts and the United States Supreme Court. Law clerks can have a great deal of influence on the judges with whom they work. Upon completing a judicial clerkship, a law clerk often becomes very marketable to elite law firms. However, some law clerks decide they enjoy the position so much they continue to serve the judge as a law clerk in a permanent capacity. Federal clerkships A clerkship with a federal judge is one of the most highly sought positions in the legal field. Some federal judges receive thousands of applications for a single position, and even the least sought-after federal clerkships will likely be applied to by at least one thousand candidates. Successful candidates tend to be very high in their class, with most being members of their law school's law review or other journal or moot court team. Such clerkships are generally seen as more prestigious than those with state judges. Almost all federal judges have at least one law clerk; many have two or more. Associate Justices of the U.S. Supreme Court are allowed four clerks. Although the Chief Justice is allowed to hire five clerks, Chief Justice Rehnquist hired only three per year, and Chief Justice Roberts usually hires only four. Generally, law clerks serve a term of one to two years; however, some federal judges hire a permanent law clerk. Such judges usually have one permanent law clerk and one or two law clerks who serve on a term basis. The most prestigious clerkship is one with a U.S. Supreme Court Justice; there are only 37 of these positions available every year. However, in recent times securing a federal court of appeals clerkship with a federal judge has been a prerequisite to clerking on the Supreme Court. Therefore, usually the second most prestigious place to clerk is at one of the U.S. courts of appeals. Clerkships with certain appellate judges, such as J. Michael Luttig, who have sent many clerks on to the Supreme Court, often called "feeder judges" are especially difficult to obtain. Luttig, before his retirement, was the leading "feeder" judge at the court of appeals level, with virtually all of his law clerks having gone on to clerk with conservative justices on the Supreme Court, a total of 40 with 33 clerking for either Justice Thomas or Justice Scalia. This reflects the increasing polarization of the court,