Helvering

'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.