History and Sources of American Law; Constitutional Law
Overview
This domain tests where American legal rules come from, how they rank against one another, and what the Constitution permits governments to do. Expect questions on the hierarchy of authority, common law and equity, judicial review, federalism, and the Commerce and Supremacy Clauses.
Sources and hierarchy
- Constitution - supreme over all other law (Article VI, Supremacy Clause).
- Federal statutes and treaties - a treaty ratified by two-thirds of the Senate has the force of federal law.
- Federal regulations - issued by agencies under delegated authority.
- State constitutions, statutes, and regulations - valid unless preempted or unconstitutional.
- Common law and equity - judge-made doctrine; stare decisis requires following precedent. Equity supplies remedies such as injunctions and specific performance when damages are inadequate.
Constitutional structure
Article I grants enumerated powers (commerce, taxing, spending, bankruptcy, patents); Article II creates the executive; Article III the judiciary; Article IV guarantees full faith and credit and privileges and immunities. The Bill of Rights originally bound only the federal government; the Fourteenth Amendment incorporated most protections against the states. Marbury v. Madison (1803) established judicial review.
Commerce Clause. Congress may regulate interstate commerce, its instrumentalities, and activities with a substantial effect on it (Wickard v. Filburn). United States v. Lopez held that possessing a gun near a school was not economic activity and exceeded the commerce power. Police power - health, safety, and morals - is reserved to the states by the Tenth Amendment.
Worked example
A state enacts a labeling rule for a drug already approved and labeled under federal law. Because the federal scheme requires uniform labeling, the state rule obstructs federal purposes and is preempted under the Supremacy Clause. Overlap alone is not enough; ask whether Congress intended to displace state law through express, field, or conflict preemption.
Traps
- Constitutional rights generally require state action; they do not regulate purely private conduct.
- The commerce power is broad but not unlimited; noneconomic intrastate activity may fall outside it.
- Courts sometimes uphold mandates under the taxing power even when the commerce power fails (NFIB v. Sebelius, 2012).
- Preemption is not automatic - state law survives unless it conflicts with federal law or Congress clearly displaced it.