US Legal Research

Introduction to researching United States federal and state law

Federal Case Law

Decisions of courts, or case law, establish precedent.  Case law is one source of legal authority, along with statutes and regulations.  Before you rely on a case, be sure to update case law to be sure another case has not overruled it.

Levels of Federal Courts image

To find relevant case law on a topic, start with a secondary source, and mine the footnotes for citations to other sources, including cases, on your topic,  Once you have looked at secondary sources, you can also search case law.

If a more recent case questions or even overrules the case you located, citators (Keycite in WestlawNext or Shepard's in Lexis Uni)  will let you know.  Citators also serve as a research tool - identifying additional cases on your topic.