The Denominator Problem: What CUSMA Is Actually Worth  ·  Part 4 of 4

Repricing the Treaty

The treaty is alive, unrenewed, and scheduled for annual physicals. That is the precise legal position, and it is worth stating precisely because each government’s July 1 statement emphasizes a different half of it. When the Free Trade Commission met for the six-year joint review, the United States “did not agree to renew the USMCA in its current form,” and so “the USMCA is not renewed,” while the agreement “remains in force pending resolution of these issues or until the Agreement’s termination” (USTR, July 1, 2026). Canada’s parallel statement emphasized that the agreement “remains fully in force until 2036 and can be renewed at any time for another 16-year period” (Global Affairs Canada, July 1, 2026).

Under Article 34.7.4, both are correct. Because a party declined to confirm extension at the six-year review, the Commission must now conduct a joint review every year, and at any time before the 2036 expiry the parties may still extend for another 16 years by written confirmation at head-of-government level (CUSMA Chapter 34 text; CRS R48787). The agreement did not die on July 1. It moved onto a one-year review cycle with a ten-year fuse, and the fuse can be unlit at any moment the three heads of government choose.

That is the treaty’s own clock. The more instructive clock is the one that ran beside it, because the first seven months of 2026 compressed the series’ entire argument into a single sequence of dates.

February 20, 2026: the Supreme Court held 6 to 3, in Learning Resources v. Trump, that IEEPA “does not authorize the President to impose tariffs” (opinion; CRS LSB11398). The statutory foundation of the 2025 tariff regime was gone. The same day, the administration signed a proclamation under Section 122 of the Trade Act of 1974, the balance-of-payments authority, imposing a 10% surcharge on most imports effective February 24, with CUSMA-compliant goods exempt, for the statutory maximum of 150 days (Federal Register, February 25, 2026). Four days from constitutional defeat to functional replacement. The preference margin for a compliant Canadian or Mexican good dipped from 25 or 35 points to 10, and stayed there.

The 150 days ran out at 12:01 a.m. on July 24. The expectation in early July, in this series’ own working notes as much as anywhere, was that the margin would now collapse toward the 2-to-4-point MFN baseline and the agreement’s value would go invisible again. That is not what happened, and the correction is more informative than the prediction. On July 23, USTR finalized tariffs under Section 301 arising from its forced-labour investigations of 60 economies, effective at 12:01 a.m. on July 24, the same minute the surcharge lapsed. Canada and Mexico sit in the lowest band, 10%, and CUSMA-compliant goods are exempt (USTR, July 23, 2026; Global Affairs Canada, July 23, 2026). The 10-point margin survived the expiry without a gap. It simply changed statutes for the third time in seventeen months.

And three days before that handoff, a fourth instrument arrived. On July 20 the administration invoked Section 338 of the Tariff Act of 1930, a discrimination-retaliation authority never before used, to impose 50% tariffs on nearly $20 billion of Canadian motor vehicles, dairy, and alcoholic beverages, effective August 19, citing Canadian retaliation and market-access grievances (USTR, July 20, 2026). Canada describes the same action more broadly, as 50% tariffs “on a series of industries ranging from hockey equipment to clothing, cement, and beer” (Prime Minister of Canada, August 22, 2026). The proclamations contain no CUSMA exemption and no expiry date; the duties run until expressly reduced, modified, or terminated (Federal Register, motor vehicles proclamation, July 23, 2026; the dairy and alcohol proclamations are parallel). For the covered goods, certification is worth nothing, exactly as it was worth nothing against Section 232 on steel, aluminum, copper, and lumber throughout 2025.

That date moved once and then arrived. Roughly two hours before the duties were due at 12:01 a.m. on August 19, the administration announced a three-day pause running through the end of Friday August 21 while the two governments tried to close a broader agreement. They did not close it. Canada suspended negotiations and recalled its negotiators on the evening of August 21, and the duties took effect on August 22. Finance Canada’s own account is the cleanest available statement of what landed: “the U.S. decision to impose a 50 per cent tariff on $27.6 billion of Canadian goods effective August 22” (Finance Canada, August 25, 2026). Note the two scopes. USTR’s July statement put the action at nearly $20 billion; Canada puts it at $27.6 billion. This series reports both and reconciles neither, because the distance between those two numbers is itself a denominator problem, and Part 1 is the reason you should not average them.

Assemble the sequence and the closing argument of this series states itself. What CUSMA (USMCA in US usage) sold, Part 3 argued, was certainty for long-lived capital. The 2025-26 record shows that certainty was partly illusory, and it failed in a specific, structural way: not one word of the agreement’s text was touched. The tariffs arrived through IEEPA, then Section 122, then Section 301, with Section 232 running continuously underneath and Section 338 now joining it, every one of them a US domestic statute operating beside the treaty rather than through it. When the Supreme Court struck the first instrument, the effect was substitution within four days, and roughly $166 billion in collected duties went into a refund pipeline that is itself still being litigated on totals that no agency publishes and that have moved every month since. When the second instrument expired, the substitution was instantaneous. The treaty’s dispute mechanisms, the ones the 2018 negotiators fought over, have been bystanders throughout.

Subsidies are the third parallel channel, and the pattern is identical in structure. CUSMA contains no meaningful discipline on domestic subsidies, so when the Inflation Reduction Act attached US-production and North American content conditions to battery and vehicle credits, investment allocation across the continent moved through a fiscal instrument the agreement does not touch, and Canada’s response, the matched production support described in Part 3, was likewise a fiscal act outside the treaty. This series deliberately makes no attempt at a subsidy-inclusive “total support” comparison across the three countries. That is a separate measurement literature with its own methods and its own denominators (the OECD’s support measurement work and the Global Trade Alert database are the places to start), and folding its softer numbers into this series’ customs arithmetic would break the measurement chain that makes the arithmetic defensible. The structural observation stands without any totals: tariffs beside the treaty, fiscal instruments beside the treaty, and a text that governs neither.

Which yields the sentence this series has been building toward. The value of CUSMA was never a property of CUSMA. The realized value of preference is the gap between the agreement’s rate and whatever the United States currently charges non-members and non-compliers, and that external rate has been set, in the last seventeen months alone, by four different US statutes, one Supreme Court decision, and one statutory expiry, every one of them a dial the United States turns unilaterally. Ottawa and Mexico City hold a certificate whose face value is denominated in a currency issued in Washington. When the US external tariff was 2%, the certificate looked worthless; at 25%, it looked priceless; both appearances were measurements of the dial, not the paper.

For a capital allocator, the operating assumptions that survive the 2025-26 record are these. Treaty preference is real and currently large: 10 points plus MFN on general trade is the difference between margin and loss for most exporters, and the certification infrastructure firms built in 2025 is a genuine asset, as Mexico’s sheltered 85% and record export year demonstrated. But preference duration should be assumed equal to the shortest relevant US statutory or political clock, not to the treaty’s 2036 horizon. Sectoral exposure must be evaluated instrument by instrument, because a good can be simultaneously CUSMA-compliant and subject to 50% duties, as Canadian vehicles have been since August 22. And any plan that depends on the difference between treaty text and US statute should price the 2026 lesson that the text does not constrain the statutes.

One clarification belongs at the end of that list, because it is the series’ hierarchy stated plainly. Capital allocation is the stakes, the flows are the scoreboard, and incidence decides how long the game runs. But the freedom to play at the level of stakes scales with size. A multinational can treat 2025 as a portfolio question and move the next plant, as Tesla did by not building one. A smaller exporter cannot move the plant at all: the asset stays where it stands, and the repricing arrives through working capital, margin, and receivables instead. The same instruments read as strategy at continental scale and as cash flow at invoice scale, and most firms in this economy live at the second one. That is why the arithmetic of Part 2 is not a footnote to the capital story; it is the form the capital story takes for everyone who cannot relocate.

The annual-review cycle now becomes the venue where all of this gets repriced, publicly, once a year until 2036 or until three signatures end the exercise. Here is what to watch.

The watch-list

Running Glossary  ·  Terms Introduced in Part 4

Section 301. Trade Act of 1974 authority to act against foreign practices deemed unfair or discriminatory; the vehicle for the July 2026 forced-labour tariffs (Canada and Mexico: 10%, CUSMA-compliant goods exempt).

Section 338. Tariff Act of 1930 authority to impose duties up to 50% on countries found to discriminate against US commerce. Invoked July 20, 2026 against Canadian vehicles, dairy, and alcohol; first use in the statute’s history; no CUSMA exemption.

Free Trade Commission. The ministerial body (USTR, Canada’s trade minister, Mexico’s economy secretary) that administers CUSMA, including the joint reviews under Article 34.7.

(Parts 1-3 defined: preference margin, utilization rate, MFN, rules of origin, TiVA, Section 122, IEEPA, Section 232, effective tariff rate, RVC, TRQ, 45X/30D, RRLM.)

A note on framing: Fully Briefed synthesizes publicly available government source material and translates it into financial terms. This is education, not legal, customs, or tax advice. The arithmetic in this series states its assumptions and sources so you can substitute your own inputs; for decisions that turn on your own tariff classification, origin documentation, or contract exposure, work with your customs broker and professional advisors.

Trevor Ryhorchuk, CPA, CIA, PMP

Fully Briefed — Canadian Trade Intelligence
tradeintel.fullybriefed.ca