“”An amicus curiae brief that brings to the attention of the Court relevant matter not already brought to its attention by the parties may be of considerable help to the Court. An amicus curiae brief that does not serve this purpose burdens the Court, and its filing is not favored.
|—United States Supreme Court Rule 37(1).
Amicus curiae is Latin for "friend of the court." The term is used for a brief submitted by someone who is not a party to a legal case, but who believes its outcome may affect their interests. There may be a positive correlation between the number of amicus curiae briefs filed in support of the United States Supreme Court agreeing to hear an appeal and it actually agreeing to hear such appeals.
The United States Supreme Court and the various Circuit Courts of Appeals permit the filing of amicus curiae briefs upon the consent of all parties to the case or by leave of court.
A more aggressive version of amicus curiae, a writ of qui tam (English: "so that") is a suit brought by a private person on behalf of the government. The person bringing suit, known as the relator, may be awarded a substantial fraction of any damages that are adjudged in the case.
A famous example is the suit filed by materials scientist and engineer Judy Wood in the aftermath of the 9/11 tragedy. Wood sued 23 respondents for failing to inform the government that the World Trade Center towers were actually destroyed by a monster directed energy weapon, not by the impact of fully loaded and fueled jetliners. The case was dismissed, and Dr. Wood was awarded precisely nothing.
- Joseph Bessette, John Pitney (2013). American Government and Politics: Deliberation, Democracy, and Citizenship - No Separate Policy Chapters. Cengage Learning. p. 446.