Independently re-verified against primary Federal Register text (documents pulled via the Federal Register API and full-text endpoints; every quote below matched verbatim). Trump did personally act on the substance of this promise: Proclamation 10908 of March 26, 2025 (90 FR 14705, effective 12:01 a.m. April 3, 2025) imposed a Section 232 tariff of '25 percent' on imported automobiles, which covers Mexican-built cars, and the May 2025 amendment (90 FR 18899) created an 'import adjustment offset' of 3.75% of aggregate MSRP (Apr 3, 2025-Apr 30, 2026) and 2.5% (May 1, 2026-Apr 30, 2027) for 'automobiles assembled in the United States' - a real, if weak, version of the promised 'build here and the tariff goes away' mechanism. But the delivered policy is materially smaller than promised on both elements. (1) The rate is 25 percent, not 100 percent, and it is a global auto tariff rather than a Mexico-border-specific one. (2) Proclamation 10908 clause (2) lets USMCA-qualifying autos certify U.S. content, with the 25% applying 'exclusively to the value of the non-U.S. content,' so the effective rate on many Mexican-assembled vehicles is well below 25%. (3) No mechanism removes the tariff for a manufacturer that opens a U.S. plant; the offset only reduces parts duties. I searched the Federal Register for every presidential document on automobiles from May 2025 through July 2026 and found no action escalating the auto rate: the only later auto-related proclamation is the Oct 22, 2025 medium/heavy-duty vehicle action, and the Feb 24, 2026 Section 122 'temporary import surcharge' is only 10% and expressly excludes both Section 232 articles and goods entered free of duty as goods of Mexico or Canada under USMCA. Meanwhile EO 14389 of Feb 20, 2026 terminated the IEEPA southern-border duties, so the total tariff burden on Mexican goods moved down, not toward 100%. Fairness check under a party-blind standard: a promise of a headline number that is delivered at one quarter of that number, with a large carve-out and without the promised escape mechanism, is 'kept some but not all' - the same label I would apply to, e.g., a $15 minimum-wage promise delivered as a narrower $10 rule. ATTEMPTED would understate a tariff that was actually imposed and is still collected 15 months later; CHAMPIONED (which scores higher) would overstate a result that landed far short of the stated terms. PARTIAL stands. REVISE rather than CONFIRM solely to fix sourcing: the prior rating's Tax Foundation citation ('USMCA-compliant imports are exempt from the tariffs indefinitely') describes the IEEPA Mexico/Canada tariffs, not the Section 232 auto tariff - USMCA autos are NOT exempt from the 232 tariff, only their U.S.-content share is deducted - and that claim is now stale after EO 14389. It is replaced with primary sources verified in this pass.