Includes
'Includes' as non-exclusive: Helvering v. Morgan's settled the question at apex in 1934
The construction rule for 'includes' and 'including' in tax statutes was substantively decided by the Supreme Court in 1934 — at apex, on the merits, citing the Revenue Act's own internal construction rule. The 1934 holding is the apex anchor for what 26 U.S.C. § 7701(c) now codifies. Subsequent re-raisings of the question (the Federal-Zone-style tax-protester line) are routed to lower courts that apply this binding precedent rather than re-examine it.
The Federal Zone Thesis at Its Foundation
Paul Andrew Mitchell's *The Federal Zone* (1992; 11th ed. 2001) builds an elaborate territorial-limits argument on three foundational moves: a re-reading of the Supreme Court's 'three meanings' of 'United States' from Hooven & Allison, a restrictive reading of the IRC's definition of 'State,' and a restrictive reading of the IRC's use of 'includes.' The structural argument depends on each foundation holding. None of the three holds against primary sources. § 7701(c) — the IRC's own construction rule — directly forecloses the central move.
'Includes' in the Internal Revenue Code
26 U.S.C. § 7701(c) is the IRC's own rule for how the words 'includes' and 'including' should be read in IRC definitions. The rule says the listed items do not exclude other things within the ordinary meaning of the defined term. This single sentence forecloses the restrictive-includes reading on which a substantial part of alternate-tax theory depends.