govinfo provides free public access to official publications from all three branches of the Federal Government. It is a service of the United States Government Publishing Office (GPO), a Federal agency in the legislative branch.
A federated search engine that searches multiple U.S. Federal government databases, retrieving reports, articles, and citations while providing direct links to selected resources available online.
“Slip” opinions consisting of the majority or principal opinion, any concurring or dissenting opinions written by the Justices, and a prefatory syllabus prepared by the Reporter’s Office that summarizes the decision.
The Constitution of the United States of America: Analysis and Interpretation (popularly known as the Constitution Annotated) contains legal analysis and interpretation of the United States Constitution, based primarily on Supreme Court case law. (From Congress.gov.)
An annotated version of The U.S. Constitution containing legal analysis based on Supreme Court decisions with links to case summaries that include lists of Supreme Court decision in which they are cited. (From the Legal Information Institute at Cornell Law School.)