Sources of Law

Constitution

A foundational legal document that establishes a government, grants its powers, and sets the limits on those powers. In the United States the federal Constitution sits at the top of the hierarchy, and every other source of law must yield to it. State constitutions play the same role within their own states.

Statute

A law enacted by a legislature, such as Congress or a state legislature. Statutes are organized by subject into codes, like the United States Code, so a researcher can find all the law on a given topic in one place. A statute can override conflicting common law but must itself yield to the constitution.

Regulation

A binding rule issued by an executive or administrative agency under authority that a statute delegates to it. Agencies fill in operational detail that a legislature leaves open, following procedures set by the Administrative Procedure Act. Final regulations are compiled in the Code of Federal Regulations.

Case Law

Law developed through written judicial opinions that decide actual disputes. When a court interprets a statute, a regulation, or the constitution, that interpretation becomes part of the law others rely on. Courts also develop common law, the body of doctrine built up through decisions in areas the legislature has not fully addressed.

Stare Decisis

The principle that a court should follow the reasoning of earlier decisions when later cases raise the same question. It gives the law predictability and treats similar parties alike. Higher-court precedent binds the courts below it within the same jurisdiction.

Supremacy and Hierarchy of Authority

The ordering rule that decides which source controls when sources conflict. The federal Constitution is supreme, followed by federal statutes and treaties, then federal regulations, with valid case law interpreting each. The Supremacy Clause resolves conflicts between federal and state law in favor of federal law within the federal government’s proper sphere.

Administrative Agency

A government body created by statute and given authority to carry out a particular area of law, such as the EPA or the SEC. Agencies issue regulations, enforce them, and often adjudicate disputes within their jurisdiction. They sit inside the executive branch but exercise powers that touch all three branches.

Part 1: Build Your Foundation

Start by getting the landscape clear in your own head before you test anything. Run Sources Explainer to get a plain explanation of the four primary sources and how the hierarchy among them works, and use Lawmaking Walkthrough to follow how a bill becomes a statute and how an agency turns statutory authority into a binding regulation. Then read Blackstone’s Section the Third on the laws of England, listed in Resources, and use Blackstone Translator to work through any passages that resist a modern reader. Blackstone is where the common law habit of reasoning from prior decisions enters the tradition you are studying, so spend real time with the original rather than only the AI’s gloss of it.

Part 2: Generate a Research Map

Now pick a current legal issue that interests you and use Case Study Mapper to produce a short account of how the Constitution, a statute, an agency regulation, and recent case law all bear on it. Treat the result as a map, not as the territory. The AI will name specific provisions, statutes, regulations, and cases. Write each one down exactly as the AI states it, because the next Part is about checking every one of those claims against the source itself.

Part 3: Verify Against the Sources

This is the core of the activity. Take the map from Part 2 and find each primary source the AI named. Read the constitutional provision in the text at Cornell’s Legal Information Institute. Find the statute in the United States Code and read the relevant section, not a summary of it. Locate the regulation in the eCFR. Pull the case through Westlaw Campus from the library, or use Google Scholar’s case law search, and read what the court actually held. As you go, use Citation Auditor to keep a running log of what the AI got right, what it got wrong, and anything it invented outright, such as a statute that does not exist or a case that does not say what the AI claimed. Note especially any place where reading the original changed your understanding of the issue.

Part 4: Write Your Findings (400 to 600 words)

Write up what you found. Open by identifying the issue you investigated so a reader has context. Then spend the body of the post on the comparison: what was the most significant difference between the AI’s summary and the actual text of a statute, regulation, or opinion you read. Discuss which of the four sources was hardest to find or understand, and why. Close by explaining how the work of digging for original sources changed your sense of where law comes from, and state your single most important takeaway. Keep the post between 400 and 600 words.

Part 5: Share Chat Link

Include one AI chat link with a 1–2 sentence explanation of what the conversation shows and why you chose to share it.

Sources Explainer

You are explaining the U.S. legal system to a college student in an Introduction to Law course who is new to legal study. In full paragraphs, with no bullet points, explain the four primary sources of American law: constitutional law, statutory law, administrative regulations, and case law. For each, describe where it comes from, what authority it carries, and how it works in practice. Then explain the hierarchy among them: why the Constitution is supreme, how statutes relate to regulations, and how courts interpret and apply both. Define the terms statute, regulation, judicial precedent, and administrative agency as you use them. Connect each source to the branch of government that produces it. Keep the language precise but accessible to someone encountering legal terminology for the first time.

This prompt sets a role and an audience, then asks for structured coverage of every source rather than a loose overview. Naming the four sources and the terms to define forces the model to be complete instead of drifting toward whatever it finds most interesting.

Lawmaking Walkthrough

You are walking a college student through how law gets made, in full paragraphs with no lists. First explain how Congress turns a bill into a statute: introduction, committee review, floor debate, voting, reconciliation between the chambers, and presidential action, defining terms like markup, conference committee, and veto override as they come up. Then explain how Congress delegates authority to an agency through enabling legislation, and how the agency uses that authority to make a binding rule through notice-and-comment rulemaking under the Administrative Procedure Act: proposed rule, publication in the Federal Register, public comment, and final rule. Finish by explaining where statutes end up (the United States Code) and where final regulations end up (the Code of Federal Regulations).

Asking the model to move step by step through two linked processes is decomposition: breaking one large question into ordered parts the model handles in sequence. This is the same move that later powers multi-step AI workflows, where each stage feeds the next.

Blackstone Translator

I am reading William Blackstone’s Commentaries on the Laws of England, Volume 1, Introduction, Section the Third, titled “Of the Laws of England” (1765). I will paste passages from it. Rewrite each passage in plain modern English while keeping its legal precision and its reasoning intact. Do not flatten the distinctions Blackstone is drawing. Leave any Latin phrases or legal maxims as they appear, and explain them briefly only when needed for clarity. Keep the tone formal and the output in full paragraphs. After each rewrite, note in one sentence anything in the passage that connects to how American courts still reason from precedent today.

Feeding the model the actual passage and asking it to translate rather than summarize keeps the original text as the anchor, so you can compare its rewrite against Blackstone’s words instead of trusting a paraphrase you cannot check.

Case Study Mapper

You are helping a college student in an Introduction to Law course see how the four primary sources of American law interact in one real situation. Research a current legal or policy issue or court case from within the last twelve months in which the U.S. Constitution, a statute, an agency regulation, and recent case law all play a part. In full paragraphs, identify the issue, then explain the constitutional provision or right involved, the specific statute that applies, the specific agency regulation at issue, and how courts have recently interpreted or enforced the law. For every source, give the exact citation: the article or amendment, the United States Code title and section, the Code of Federal Regulations citation, and the case name with court and year, so each one can be looked up and verified.

Demanding exact citations for every source turns the AI’s summary into a set of checkable claims rather than a vague narrative. You are deliberately setting up the next step, where you verify each citation against the primary source, so the prompt is written to make that verification possible.

Citation Auditor

I am going to give you a legal summary an AI produced, along with the citations it included: a constitutional provision, a United States Code section, a Code of Federal Regulations citation, and a case name. For each citation, tell me what to look for when I check it against the primary source, and what would tell me the AI got it wrong, fabricated it, or described it inaccurately. Do not confirm that any citation is correct on your own authority, and say plainly that the only way to know is for me to read the actual constitutional text, statute, regulation, and opinion myself. Give me a short checklist I can use as I verify each one.

This prompt treats the AI as a verification aid rather than an authority, and it explicitly blocks the model from vouching for its own citations. Models are prone to inventing plausible-looking statutes and cases, so building the habit of confirming every authority against the primary source is the single most important safeguard in AI-assisted legal research.