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Law Library

Sources of Law and Types of Authority: Sources of Law

Authoritative Texts (the "Law")

In the practice of law, you will be looking for the law, or “legal authority” that is pertinent to your case.  You hope that you will find legal authority that will cause a court or administrative agency to say “you win.”

So what are our sources of authority?

  • Remember that the United States Constitution forms the basic law. It establishes the legal framework of the government.
  • Then remember that each of the “three branches” are going to provide you with primary legal authority.
  • The "Law" will be the result of the interaction between the relevant texts from some or all branches (and levels) of government

Summary of Sources and Texts

  • Judicial Branch
    • Cases/Opinions (Usually at the Appellate Level)
    • Common Law (Judge-made Law)
    • Interpretation of Statutes, Regulations Opinions issued by Courts
  • Legislative
    • Statutes enacted by elected bodies
  • Executive
    • President
      • Executive Orders and Directives
    • Administrative Bodies
      • Rules and Regulations