American common law vs British common law

English common law is the root — but America grew its own legal order from it. Getting this right means holding two true things at once: the states received English common law, and America then developed its own, at both the state and federal levels.

1. Reception: English common law came over — on each state’s terms

The original colonies, and later the states, received the English common law by reception statutes. Each state fixed its own reception date and terms, keeping English common law except where its own constitution and statutes changed it. So there is no single “American common law” inherited whole from England — there are fifty state common-law traditions, each with an English root and its own subsequent growth.

2. Federal courts: “there is no federal general common law”

On the federal side, the landmark is Erie Railroad Co. v. Tompkins, 304 U.S. 64 (1938). Justice Brandeis, overruling Swift v. Tyson (1842), held that when a federal court hears a state-law claim (in diversity), it must apply state law — there is no federal general common law for the federal courts to make up. That is the accurate, load-bearing statement of the rule.

“There is no federal general common law.” Erie R.R. Co. v. Tompkins, 304 U.S. 64 (1938) (Brandeis, J.).

3. But federal law is still made by federal courts — in two accurate senses

(a) Surviving federal-common-law enclaves. Erie ended general federal common law, not all of it. Federal courts still fashion common-law rules in narrow, genuinely federal areas — for example admiralty and maritime law, disputes between states, foreign relations, and the rights and duties of the United States itself.

(b) The federal judicial power over federal and constitutional questions. When the question is one of federal statute or the Constitution, the federal courts — with the Supreme Court at the top — are the authority, and their rulings bind nationwide. This is the accurate version of the idea that America has its own overriding body of national law: it is the federal judicial power over federal/constitutional law, not a free-floating “federal common law” of general subjects.

The ACA example: a national question, decided for the whole country

A clean illustration is National Federation of Independent Business v. Sebelius, 567 U.S. 519 (2012). The Court upheld the Affordable Care Act’s individual mandate — not under the Commerce Clause, but as a valid exercise of Congress’s taxing power (Chief Justice Roberts writing; decided June 28, 2012). Whatever one thinks of the result, it shows the mechanism: a federal court resolving a national, constitutional question, and that ruling binding every state. That is the federal judicial power at work — the accurate core of the “America has its own law” point.

A worked example — a Black’s maxim (“property lines in the sky”), applied AND cabined by courts

This is the Black’s-Law lesson in miniature: a Latin maxim lives in the dictionary, but its force comes from how common-law courts apply and limit it — never from the dictionary entry itself. Take the classic property maxim Cuius est solum, eius est usque ad coelum et ad inferos — “whose is the soil, his it is all the way up to the sky and down to the depths” — the ad coelum doctrine. It reaches Black’s from Blackstone’s Commentaries on the Laws of England (1766), and in its old, literal form it said a landowner owned the column of air to the heavens.

How a court cabined the maxim: United States v. Causby, 328 U.S. 256 (1946). When military aircraft flying low over a North Carolina farm ruined a chicken business, the Supreme Court held the government had taken an easement in the low airspace the owner actually used — but it flatly refused the literal ad coelum rule. Justice Douglas, writing for the Court, put it directly:

“It is ancient doctrine that at common law ownership of the land extended to the periphery of the universe — Cujus est solum ejus est usque ad coelum. But that doctrine has no place in the modern world. The air is a public highway, as Congress has declared.” United States v. Causby, 328 U.S. 256, 260–261 (1946) (Douglas, J.).

That is the whole point: the maxim is real and it is in the dictionary, but a court decided how far it reaches. Causby kept a property line in the low, usable air and cut the maxim off before it could ground every airliner in a trespass suit. A dictionary maxim is the starting point of the argument, not the law.

The other direction — Justice Scalia reviving common-law property lines for the Fourth Amendment. If Causby shows a court trimming an old property maxim, Scalia’s late opinions show a Justice resurrecting common-law property boundaries to decide modern cases. In United States v. Jones, 565 U.S. 400 (2012), Scalia’s majority held that attaching a GPS tracker to a car and using it to follow the car is a Fourth Amendment “search,” because a vehicle is an “effect” and the government “physically occupied private property for the purpose of obtaining information” — a common-law trespass. He reminded the Court that its Fourth Amendment law “was tied to common-law trespass, at least until the latter half of the 20th century.”

“The Government physically occupied private property for the purpose of obtaining information. We have no doubt that such a physical intrusion would have been considered a ‘search’ within the meaning of the Fourth Amendment when it was adopted.” United States v. Jones, 565 U.S. 400, 404–405 (2012) (Scalia, J.).

The next year, in Florida v. Jardines, 569 U.S. 1 (2013), Scalia’s majority carried the same common-law property logic into the vertical/near dimension of the home: bringing a drug-sniffing dog onto the front porch — the home’s curtilage — was an unlicensed physical intrusion, and therefore a search. Same method as Jones: the boundary is drawn by common-law property tradition, not by a privacy formula or a dictionary line.

Honest scope note — we are not putting words in Scalia’s mouth. Scalia’s Jones and Jardines opinions rest on common-law trespass (tracing it through cases like Entick v. Carrington); they do not expressly invoke the ad coelum maxim, and neither opinion uses that phrase. So we present the two accurately and side by side rather than merged: Causby is the case that names and limits ad coelum for airspace, and Jones/Jardines are Scalia using common-law property lines — on a car, and up to the curtilage of a home — to decide Fourth Amendment questions. They are the same underlying idea (property lines, including in the air and at the edge of the home, fixed by common-law tradition rather than by a dictionary entry), reached through different doctrines by different Justices.

The maxim ad coelum sits in Black’s; but Causby is what tells you how high it goes, and Scalia’s trespass revival is what put common-law property lines back at the center of the Fourth Amendment. The dictionary supplies the phrase — the courts supply the law. Teaching synthesis of Causby (1946) and Jones (2012) / Jardines (2013).

Related: binding vs. persuasive authority · reception of English law & the earliest American cases.