The role of the special master (who is frequently, but not necessarily, an attorney) is to supervise those falling under the order of the court to make sure that the court order is being followed, and to report on the activities of the entity being supervised in a timely matter to the judge or the judge's designated representatives. Special masters have been controversial in some cases, and are often cited by conservatives in the United States as an example of judicial supremacy over the other branches of government. For example, at times they have ordered the expenditure of funds over and above the amount appropriated by a legislative body for the remediation of the situation being examined. To this point, their powers have generally be found to be valid and their remedies upheld by United States courts.
In the aftermath of the September 11, 2001 attacks in the United States, then Attorney General John Ashcroft appointed Kenneth R. Feinberg as special master to oversee the dispensation of an $11 billion victim's compensation fund.
The United States Supreme Court will normally assign original jurisdiction disputes (cases such as disputes between states that are first heard at the Supreme Court level) to a special master to conduct what amounts to a trial court (the taking of evidence and a ruling). The Supreme Court can then assess the master's ruling much as a normal appeals court would, rather than conduct the trial itself.