The US Supreme Court rules that congressional legislation that diminished the size of the Sioux people's reservation thereby destroyed the tribe's jurisdictional authority over the area in Rosebud Sioux Tribe v. Kneip.

The Supreme Court of the United States (SCOTUS) is the highest court in the federal judiciary of the United States. It has ultimate appellate jurisdiction over all U.S. federal court cases, and over state court cases that turn on questions of U.S. constitutional or federal law. It also has original jurisdiction over a narrow range of cases, specifically "all Cases affecting Ambassadors, other public Ministers and Consuls, and those in which a State shall be Party." In 1803, the Court asserted itself the power of judicial review, the ability to invalidate a statute for violating a provision of the Constitution via the landmark case Marbury v. Madison. It is also able to strike down presidential directives for violating either the Constitution or statutory law.

The Sioux or Oceti Sakowin are groups of Native American tribes and First Nations people from the Great Plains of North America. The Sioux have two major linguistic divisions: the Dakota and Lakota peoples. Collectively, they are the Očhéthi Šakówiŋ, or 'Seven Council Fires'. The term Sioux, an exonym from a French transcription of the Ojibwe term Nadowessi, can refer to any ethnic group within the Great Sioux Nation or to any of the nation's many language dialects.

April 5 is the 95th day of the year in the Gregorian calendar; 270 days remain until the end of the year.