Norton v. Southern Utah Wilderness Alliance
Holding that agency can be compelled to act if time period is specified by law.Norton v. Southern Utah Wilderness Alliance, 542 U.S. 55 (2004), was a Supreme Court case that held that although the Administrative Procedure Actsays that a person may challenge an agency's failure to act, this provision essentially just carries forward the writ of mandamus. Thus an agency cannot be compelled to act unless there is some non-discretionary, discrete act.
(from Wikipedia)