Expressio Unius Est Exclusio Alterius

Jan 1, 0001

Expressio unius est exclusio alterius — “the express mention of one thing excludes others” — is a canon of statutory construction that goes back to medieval English common law and is part of the standard interpretive toolkit of every U.S. court. The closely related variant inclusio unius est exclusio alterius (“the inclusion of one is the exclusion of another”) applies the same idea directly to “includes” formulations.

In its general operation: when a statute lists certain items, the canon supplies a presumption that items not listed are excluded from the statute’s reach. If a regulation provides that “the following sources of income are taxable: A, B, C,” the canon presumes that source D — not listed — is not taxable.

The canon is real, the canon is invoked routinely by federal courts, and the canon does substantial interpretive work in cases where the statute is otherwise ambiguous about the exhaustiveness of a list. Any honest engagement with statutory-interpretation arguments — in tax law or elsewhere — has to treat the canon as a real interpretive tool.

The canon is a presumption, not an absolute rule

What the canon’s invocation in alternate-tax theory often obscures is that expressio unius operates as a defeasible presumption — a default that can be rebutted, displaced, or set aside in particular cases. Every standard treatise on statutory interpretation (Sutherland Statutory Construction; Scalia & Garner, Reading Law) catalogues the conditions under which the canon yields. Five common ones:

Express statutory language to the contrary. When the legislature speaks directly to whether a list is exhaustive or illustrative, that express choice controls. Expressio unius operates only in the absence of such guidance.
Conventional drafting cues. “Include,” “such as,” and “including but not limited to” are conventional non-exhaustive markers. When a statute uses them, courts generally treat the listed items as illustrative rather than exhaustive — even without an express override.
Other canons pointing the other way. Ejusdem generis, the rule against surplusage, the whole-act rule, and the reasonable-meaning canon all frequently produce results different from expressio unius. Courts weigh canonical guidance rather than mechanically applying a single canon.
Context indicating non-exhaustive intent. Where the listed items are clearly illustrative — for instance, where the list expresses a category that has many members and only a few are named — the canon does not exclude unlisted members of the same category.
Absurd results. When applying the canon would produce nonsensical or self-contradictory readings, courts decline to apply it.

These limits are not contested. They appear in the leading treatises, in Supreme Court opinions discussing the canon, and in the standard approach federal courts take to canonical guidance.

How the canon appears in alternate-tax theory

The canon is the doctrinal backbone — usually unstated — of a substantial portion of alternate-tax theory. The argumentative move runs:

The IRC defines “State” to include the District of Columbia (§ 7701(a)(10)). By the canon expressio unius est exclusio alterius, items not listed are excluded. Therefore “State” in the IRC excludes the fifty states.

The same move is then made on “United States” (§ 7701(a)(9)), “employee,” “employer,” “wages,” and other defined terms. Each application produces a narrow definition that, taken together, constructs the territorial-limits / volunteer-citizen reading at the heart of theories like The Federal Zone.

The argument has surface appeal because:

The canon is real and authoritative.
The “include” formulation in IRC definitions is genuinely non-exhaustive, but readers without statutory-construction training may not know that.
The argument does not foreground the express override that Congress enacted to foreclose this exact kind of reading.

That express override is 26 U.S.C. § 7701(c):

“The terms ‘includes’ and ‘including’ when used in a definition contained in this title shall not be deemed to exclude other things otherwise within the meaning of the term defined.”

§ 7701(c) is precisely the kind of express statutory rule that displaces the canon’s presumption. Congress, drafting the IRC’s general definitional section, anticipated that “include” formulations might be read restrictively (whether through expressio unius or through pre-IRC administrative interpretations) and supplied an explicit override. The canon’s presumption no longer operates for IRC definitions; the express statutory rule does.

The Supreme Court reached the same conclusion at apex in 1934. In Helvering v. Morgan’s, Inc., 293 U.S. 121 (1934), the Court construed “includes” in a Revenue Act of 1928 definition and held the term non-exclusive — relying on the Revenue Act’s own construction rule (§ 2(b), the precursor to § 7701(c)) and on the canon’s actual operation. The 1934 decision is binding precedent on substantively the same construction question. Full treatment.

Why the canon does not get Mitchell to his conclusion even on its own terms

A deeper problem with Mitchell’s-style invocation of expressio unius: even if § 7701(c) did not exist, the canon would not produce the conclusion that the fifty states are excluded from “State” in the IRC. The canon presumes that items not enumerated are excluded. The fifty states are not “items not enumerated” in any analytically useful sense — they are within the ordinary meaning of the word “State.”

The canon limits a statute’s reach to things either listed or within the term’s natural scope. It forecloses additional categories that an advocate might try to read into the statute. It does not flip the ordinary meaning of a defined word on its head. To take a non-tax illustration: if a statute provides “vehicles include automobiles, trucks, and motorcycles,” the canon would not exclude “cars” — cars are within the plain meaning of “vehicles.” The canon might exclude “horses” or “boats.” The listed items add specificity to the plain meaning, not subtraction from it.

Applied to § 7701(a)(10) (“State shall be construed to include the District of Columbia”): the fifty states are within the plain meaning of “State.” D.C. is the listed addition. Read straight, the canon adds D.C. to the ordinary meaning rather than restricting “State” to D.C. The Mitchell-style reading requires the canon to operate against the term’s plain meaning — which is not how the canon operates.

The pattern across alternate-tax theory

The same canonical move recurs across alternate-tax arguments — not just in The Federal Zone but in dozens of derivative texts. The pattern is:

Quote a defined term from the IRC that uses “include.”
Invoke expressio unius (sometimes by name, often implicitly).
Conclude that the term excludes everything not listed.
Build doctrinal consequences from the narrow reading.

The pattern fails for the same reasons in every case:

§ 7701(c) supplies Congress’s express override for the entire IRC.
The “include” formulation is conventionally non-exhaustive in legal English; § 7701(c) makes that conventional reading explicit.
The canon, even on its own terms, does not exclude items within a term’s ordinary meaning.

Restoring the canon’s actual operation — defeasible presumption, yields to express override, does not flip ordinary meanings — and restoring § 7701(c) to its operative position closes the canonical move that a substantial fraction of alternate-tax theory depends on.

This concept is treated in essay form in The Federal Zone Thesis at Its Foundation and pairs with the “Includes” in the IRC and “State” in the IRC concept pages.