CAN THE PRESIDENT JUST CANCEL CUSMA?

While Ottawa and Washington sit across the trade table this week, Canada’s trade lawyers keep telling reporters the President legally cannot walk away. Congressional statute says otherwise.

Appleton’s CLAUSE & EFFECT, August 7, 2026

Dominic LeBlanc was back in Washington this week.1 So was Canada’s chief trade negotiator, Janice Charette. The talks are real, and they may well succeed. Mark Carney says the tone is “quite firm.” 2 There are a lot of hurt feelings and recriminations at that negotiation table. Nobody involved is pretending this will be easy.

No matter how promising things may be, talks can fail. And when a room full of Canadian trade lawyers gets asked what happens if they do, the answer keeps coming back the same way: the President cannot simply cancel CUSMA. Congress would have to agree first.

That answer is false, and it is worth correcting in public before it hardens into conventional wisdom on this side of the border.

Congress already gave its approval. It gave it six years ago, in the statute that brought CUSMA into force inside the United States, and it wrote that approval so that no future vote is required to use it.

Section 621 of the USMCA Implementation Act, codified at 19 U.S.C. § 4621,3 says this:

On the date CUSMA ceases to be in force with respect to the United States, this Act and the amendments made by it cease to have effect.

That is a self-executing sunset. Congress wrote its own repeal in advance and pointed the trigger straight at a decision the President controls.

Read it again. The reassurance Canadians are hearing assumes a President who withdraws internationally leaves the American implementing law standing behind him, a zombie statute nobody can kill without a fresh act of Congress. Section 4621 forecloses that scenario by design. There is no separate repeal to force through the House and Senate. The statute repeals itself, automatically, the moment CUSMA stops being in force for the United States.

The general rule that a President cannot cancel an act of Congress on his own is correct. It just isn’t the rule that governs here. Congress did the repealing itself, in advance, conditional on the President’s decision. That is entirely within Congress’s power, and in January 2020 it used that power.

CUSMA’s predecessor gives away how deliberate this was.

Section 109(b) of the NAFTA Implementation Act 4 was genuinely unclear on this exact point. The Congressional Research Service said so in March 2019:5 the language and history suggested Congress meant that provision to apply if Canada or Mexico left while the United States stayed in, not the reverse, and reading it more broadly would raise a constitutional problem.

Ten months later, Congress rewrote the rule for CUSMA. It supplied precisely the language the Congressional Research Service had found missing, an explicit clause tied to CUSMA “ceasing to be in force with respect to the United States.” That is not an accident of drafting. That is Congress being told its language was ambiguous, and fixing it, in the executive’s favour.

The Justice Department’s Office of Legal Counsel (OLC) gives the executive branch its authoritative internal legal opinions. On the predecessor question, it has already spoken, twice.

In October 2018, OLC concluded 6 that the President could lawfully withdraw the United States from NAFTA without any further action from Congress. Its reasoning: Congress authorized the President to carry out NAFTA and placed no limit on his power to leave it.

CUSMA’s statute goes further than NAFTA’s did. It doesn’t just decline to limit the President. It affirmatively states what happens if he withdraws, in section 4621. If OLC was comfortable concluding the President could walk from NAFTA on the strength of congressional silence, USMCA is not a harder case. It’s an easier one.

In 2020, OLC went one step further still,7 concluding the President’s power to withdraw from treaties generally cannot be restricted by Congress at all, even by an explicit statute demanding advance notice.

Under the 2018 opinion, the President can withdraw from CUSMA because Congress imposed no limit. Under the 2020 opinion, it would not matter if Congress had tried.

Trace the “you need Congress” line back far enough, and it lands on a single sentence in a Senate committee report,8 written alongside the CUSMA implementing bill. The report says the joint review process doesn’t change the constitutional balance, and that the United States cannot withdraw from a trade agreement without Congress’s consent.

That sentence is not the law. It is a committee’s description of the law, filed in a report nobody voted on, and it directly contradicts the statutory text Congress passed in the very same bill. When a committee report and the enacted statute point in different directions, the statute wins. No court has ever had reason to say otherwise, because no President has yet tested it.

There is a real consultation requirement layered on top of all this. Section 611 of the implementing law.9 does require the President to consult certain congressional committees before each joint review and to report on his recommendations. That happened, on schedule, this year, when the United States declined to confirm extension of USMCA -CUSMA at the July 2026 review.10

Consultation is not consent. The United States already declined to confirm extension of u USMCA at the July 2026 review. No congressional vote occurred. Consultation happened. Consent was never on the table, because it was never legally required.

Congress has, in fact, written the other kind of clause. It just didn’t write it for CUSMA.

In December 2023, Congress passed a law11 barring the President from withdrawing the United States from NATO without a two-thirds Senate vote or a separate act of Congress. It is, by every account, the first statute of its kind, ever enacted for any treaty or agreement.

Congress has the drafting template sitting right there. It used it exactly once, for the North Atlantic Treaty. It has never used it for USMCA -CUSMA. Instead, in the very statute governing USMCA, three years earlier in January 2020, it had already written the opposite provision entirely.

If Congress had wanted USMCA protected the way it protects NATO, it knew precisely how to say so. It said something else.

This piece went to press the same week correspondence crossed my desk asking whether this year’s Supreme Court ruling against the IEEPA tariffs changes any of the above. It doesn’t, but the reasoning is worth a paragraph because the ruling gets invoked loosely.

In February, the Supreme Court held12 that the emergency powers statute Trump used to impose his first-term tariff regime, IEEPA, never authorized tariffs in the first place. Six Justices agreed on that reading of the text. A narrower group of three went further and invoked the doctrine that courts require a clear statement from Congress before reading sweeping new power into vague language.

Section 4621 is not vague language. It is Congress being as clear as a legislature can be, saying exactly what happens and exactly when. Whatever the ruling means for emergency tariff powers, it has nothing to say about a statute that never asked anyone to read anything in. The clear statement is already sitting on the page.

None of this means that USMCA -CUSMA withdrawal would be tidy. If it happens, it is not going to be pretty. Two real questions remain open, and Canada would do well to have public answers to both before either one becomes live rather than after.

If section 4621 switches off the implementing Act, does the American tariff schedule snap back to pre-CUSMA rates automatically, or does US Customs need a fresh presidential proclamation first? The statute is silent. That gap would generate genuine confusion at the border, for every entry, on day one.

And the original 1988 Canada-US Free Trade Agreement was suspended, not terminated, when NAFTA replaced it. Whether it revives on CUSMA’s end is a contested question of treaty law nobody has resolved. Canada should have a considered legal position on it now, not after the fact.

Talks in Washington may still land somewhere workable. Nothing above predicts otherwise. But the planning conversation Canadians are having right now assumes a congressional veto that does not exist in the statute Congress actually passed. That is worth fixing regardless of how the negotiation ends.

Code before clause.

Barry Appleton is Interim Director of the Balsillie Legal Advisory Centre at the Balsillie School of International Affairs, Managing Partner of Appleton & Associates International Lawyers LP, and Co-Director and Distinguished Senior Fellow at the Center for International Law at New York Law School. He was an advisor in the original NAFTA negotiations on behalf of Ontario. © 2026 Barry Appleton. All rights reserved

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