constitution.congress.gov
Unknown
Official, annotated version of the U.S. Constitution from the U.S. Congress. It presents the full text of the Constitution and its amendments, paired with historical notes, explanations, and cross-references to aid learning in constitutional law.
More resources on Constitutional Law Basics
oyez.org
Oyez is a multimedia archive of U.S. Supreme Court cases. It provides official audio of opinions, full text opinions, case summaries, transcripts, and background on justices and landmark rulings—an essential resource for learning constitutional law basics.
ConSource
A free digital library from the Constitutional Sources Project holding drafting and ratification records of the U.S. Constitution, indexed clause by clause so readers can trace any provision back to its founding-era documents.
The Constitution, the Articles, and Federalism: Crash Course US History #8
Intro to US policy-making process by John Green, highly recommended in r/PoliticalScience
American Government
Learn US government and public policy through engaging videos and practice exercises! Free course from Khan Academy.
We the People
Weekly podcast from the National Constitution Center in which scholars from opposing viewpoints debate a live constitutional question, such as free speech, executive power or Supreme Court rulings. Listeners hear the strongest arguments on each side and learn how constitutional text and precedent are applied.
Criminal Procedure: A Free Law School Casebook (2nd Edition)
Complete law school casebook on the Fourth, Fifth, and Sixth Amendments: searches and seizures, custodial interrogation and Miranda, the exclusionary rule, the right to counsel, and eyewitness identification, assembled from edited Supreme Court opinions with connecting notes.