A court ruling is any decision made by a judge or other official. The terms “decision,” “order,” and “opinion” are often used interchangeably, but they all refer to the act of delivering a ruling in a particular case, or the text that records that ruling. A decision can affect (dispositively or nondispositively) more than one case, and may consist of more than one document.
An opinion is a written statement by a judge that explains why a court has reached a decision. An opinion typically begins with a history of the facts and legal issues in the case, then analyzes those facts using relevant statutes and past decisions (precedent). Finally, it makes a ruling based on that analysis. An opinion may be in the form of a majority or dissenting judgment.
In order to be reviewed by the Supreme Court, a case must meet certain criteria, including a sufficiently developed appellate record and the existence of a federal issue not already resolved by a lower court. Exceptional circumstances may justify the Court invoking its own independent discretion, however.
The Justices of the Supreme Court write a variety of opinions in cases in which they have heard oral argument, usually in the form of a majority or principal opinion. In addition, Justices sometimes write opinions to dispose of a case summarily without having heard oral argument or in the form of an in-chambers or per curiam opinion. These are not published, although the Reporter of Decisions may include a summary.