Washington switches on 50 per cent Section 338 duties on roughly US$20 billion of Canadian goods after three days of talks collapse. Ottawa promises a matching strike on September 8, and for the first time in the CUSMA era a valid certificate of origin buys an importer nothing.
OTTAWA, AUGUST 24, 2026
The United States began collecting an additional 50 per cent duty on hundreds of Canadian products at 12:01 a.m. Eastern time on Saturday, August 22, after a three day negotiating extension expired without an agreement. Prime Minister Mark Carney suspended the talks, recalled Canada’s negotiating team from Washington, and pledged that Ottawa would answer with countermeasures of equivalent value on Tuesday, September 8, the first business day after Labour Day.
The measure covers roughly US$20 billion of annual Canadian exports, about 5 per cent of everything Canada ships south, according to figures cited by the Associated Press and Al Jazeera. What makes it unusual is not the rate. Canada has lived with 50 per cent duties on steel and aluminum under Section 232 for more than a year. What makes it unusual is the statute behind it and the fact that Canada’s preferential access under the Canada United States Mexico Agreement does not switch it off.
“Canada will match those tariffs dollar for dollar to protect our workers and businesses,” Carney said in a statement issued minutes after the deadline passed, as reported by Fortune and NPR. At a press conference in Ottawa on Saturday, asked whether the country had entered a full trade war, he was blunter. “You’re at war when you get attacked. We got attacked,” he told reporters, according to NPR’s account of the briefing.
United States Trade Representative Jamieson Greer put the blame on the other side of the table. “Canada declined to finalize the trade deal under the terms agreed earlier this week,” he said in a statement read to reporters shortly before midnight and quoted by Fortune and Al Jazeera. “Despite the U.S. offer to Canada to receive the best treatment of any major exporter to our market, new demands and walk backs of other commitments by Canada have upended the careful balance reached in the past days.”
No further talks are scheduled.
What is now in force
Three presidential proclamations signed on July 20, 2026 sit behind the duty. Each targets a separate American grievance, and each imposes an additional 50 per cent ad valorem charge on a different basket of goods. Trade counsel and customs guidance published since Saturday describe the combined coverage as spanning motor vehicles, wine and other alcoholic beverages, dairy products including milk and cream, cement, furniture, plastics, plywood, electrical equipment, industrial machinery, fishing rods, seeds, jewellery, fine art, textiles and apparel, honey, wigs, tongue depressors, and hockey sticks and other hockey equipment.
The analysis published by Frequency on August 22 counts more than 550 tariff subheadings across the three proclamations. The Associated Press summarised the range more memorably, noting that the list runs “from hockey sticks to tongue depressors.”
The carve outs matter as much as the coverage. Energy products, potash, fish, and critical minerals are excluded. So are goods already subject to Section 232 duties, which means steel, aluminum and copper articles already paying the metals rate are not stacked with a further 50 per cent under this action. Civil aircraft covered by the World Trade Organization Agreement on Trade in Civil Aircraft are also outside the measure. Canada’s largest single export category by value, crude oil and refined energy, is therefore untouched.
That is why the headline exposure lands near 5 per cent of exports rather than a quarter of them. It is also why the pain is concentrated rather than diffuse. The measure is aimed squarely at value added manufacturing, processed food, and consumer goods, the parts of the Canadian export base that employ the most people per dollar shipped.
A statute from 1930
The legal instrument is Section 338 of the Tariff Act of 1930, the law American economists know better as Smoot Hawley. Section 338 permits the president to impose additional duties of up to 50 per cent on goods from any country found to discriminate against United States commerce. Unlike Section 301 or Section 232, it requires no formal investigation, no agency report, and no public comment period. It also sets no expiry date.
According to legal analysis cited in trade press coverage of the proclamations, no president had ever used Section 338 to impose a tariff before July 20 of this year. Frequency described the provision as unused for punitive tariff purposes since the 1940s and characterised the action as “legally untested and largely unilateral.” Fortune noted that the 1930 law is “notorious among economists and historians for limiting world commerce and making the Great Depression worse.”
The reach for a dormant statute has a recent history behind it. The Supreme Court ruled in February that the administration had overstepped its authority in imposing the 2025 emergency tariffs under the International Emergency Economic Powers Act, striking those duties down and opening the door to importer refunds. Section 338 is one answer to that ruling: an authority that lives in the tariff code itself rather than in emergency powers.
Each of the three proclamations names a specific Canadian practice. One cites Canada’s dairy tariff rate quotas under CUSMA, arguing that European Union cheese exporters receive more favourable access to the Canadian market than American suppliers do. A second cites a provincial surtax said to apply only to vehicles built in the United States. A third points to provincial liquor board decisions that pulled American wine and spirits from shelves without extending the same treatment to any other trading partner.
Whether those characterisations survive contact with a tribunal is a live question. Barry Appleton, senior fellow at the Center for International Law at New York Law School, framed the deeper problem in comments to the Associated Press. “Canada told the Americans in advance that if these tariffs landed, it would stop negotiating and retaliate,” he said. “The American trade representative said publicly he would not tolerate retaliation. Both sides have now committed themselves in public, which is how escalation stops being a choice.”
The CUSMA blind spot
For importers, the single most consequential design feature is this: the Section 338 duties apply to covered goods regardless of whether those goods qualify for preferential treatment under CUSMA.
Customs guidance published since the measure took effect is emphatic on the point. A valid certificate of origin does not exempt a covered product. Under the Section 122 and Section 232 regimes, CUSMA qualifying Canadian goods have generally been shielded or treated more favourably. Section 338 is built differently. It targets named products as a response to named policies, and origin status is simply not part of the test.
Frequency put it starkly, noting the proclamations apply “regardless of whether a good originates under” the agreement, and that “three decades of assumed North American preferential access offer no shelter for covered goods.”
That is the detail catching brokers and finance teams off guard this week. A furniture manufacturer in Quebec whose goods have crossed at zero duty since 1994, and whose landed cost models have a CUSMA field hard coded to zero, is now facing a 50 per cent charge on the same shipment with the same paperwork. United States Customs and Border Protection issued a bulletin to the trade on Friday warning that officers would be enforcing the new rates immediately once the deadline passed, according to NPR.
How the week fell apart
The sequence is worth setting out precisely, because the timing explains why the duty took effect automatically rather than by a fresh decision.
The proclamations were signed on July 20 with a 30 day fuse, making the original effective date 12:01 a.m. on August 19. Hours before that deadline, the White House announced a three day pause, citing progress toward a broader agreement covering market access, economic security, and digital trade. Carney confirmed the postponement ran through the end of the day on Friday, August 21.
Canada’s team, led by Canada United States Trade Minister Dominic LeBlanc and chief negotiator Janice Charette, spent the week in Washington. LeBlanc met Greer for more than three hours on Thursday and returned Friday morning. “We’re very close,” LeBlanc told reporters on Thursday afternoon in remarks reported by the Globe and Mail and aggregated by BigGo Finance. “We continue to make progress, and we’re going to stay here and do the work that’s necessary until we get to that point.”
They did not get to that point. Critically, no proclamation was withdrawn or amended during the pause, so when the pause lapsed the original 50 per cent duty took effect on its own terms.
Carney’s account of the breakdown, given at Saturday’s press conference and reported by CTV News and BNN Bloomberg, identifies two late changes. The first was sectoral. “The Americans wanted to limit it to autos only, not include medium and heavy duty trucks which is a big change, obviously,” he said. The second was constitutional in flavour rather than commercial. Carney said the United States sought to restrict Canada’s ability to conclude trade agreements with other countries, and he called that “a power play.”
In his written statement, quoted by NPR, the Prime Minister said his negotiators had worked “in good faith” for more than a year and that “last minute changes in the U.S. proposed terms were unfair, uneconomic, and called into question the reliability of any deal.” He added: “Canada has what the world wants. And we will not allow any nation to determine our future.”
Greer’s version is the mirror image. He said the American offer was “forward looking” and included “a historic economic and national security partnership,” and that earlier in the week Washington “agreed to provide even better treatment to Canada, offering significant tariff reductions on steel, aluminum, autos, and lumber.” The package, he said, would have produced supply chain coordination on aerospace, joint action on unfair trade practices, critical minerals cooperation, tougher enforcement against goods made with forced labour, and the formal launch of CUSMA renewal negotiations.
President Donald Trump posted on social media overnight Saturday, in a message quoted by NPR: “Canada wants the benefits of being a State, without being one!!! They have also charged our great farmers, for many years, massive amounts of Tariffs. No more!!!”
What Canada will do on September 8
Carney has named the shape of the response without yet publishing the schedule. Canada’s countermeasures take effect on Tuesday, September 8, and will fall on American steel, dairy products, appliances, agricultural equipment, pulp and paper, and electronics, according to his August 22 remarks reported by NPR, Al Jazeera and CNBC.
The detail that matters commercially, the tariff line list, has not been released. Carney said it would follow “in the coming days,” and as of this writing Ottawa has not published an Order in Council or a Canada Border Services Agency customs notice with the specific subheadings. That leaves Canadian buyers of American machinery, appliances, and paper products roughly two weeks to work out their exposure once the list lands.
Three practical questions will only be answered by that text. Whether the countermeasures carry a remission or duty relief process for inputs with no domestic or third country substitute, as earlier Canadian counter tariff rounds did. Whether goods already on the water on September 8 are grandfathered. And whether the measures apply to CUSMA originating American goods, given that Ottawa removed its surtax on CUSMA compliant American products in September 2025 and has been operating a narrower counter tariff perimeter since.
Carney also promised a support package for affected workers and firms, to be detailed in the coming days. Nothing has been costed publicly yet.
Reaction from the provinces and the sectors
The political response inside Canada has been notably united, at least in the first 48 hours.
Ontario Premier Doug Ford, whose province carries the largest absolute exposure, backed the walkout without qualification. “Team Canada needs to stand together more united than ever before,” he wrote late Friday. “The prime minister has my full support for a strong response, tariff for tariff, dollar for dollar.” Speaking to CP24 on Saturday, in comments reported by BNN Bloomberg, Ford framed the dispute as an “economic war” and defended the rejection of the package. “I’m glad he didn’t sign that deal because it was a bad deal for the auto sector, the steel sector, and manufacturing sector,” he said. “We never started this fight, but I can assure you, we’re going to win this fight.”
A letter Ford sent Carney on Monday, released by his office on Saturday, told the Prime Minister that “no deal is better than a bad deal” and warned that “we cannot allow arbitrary deadlines, shifting justifications or escalating tariff threats to weaken our resolve.” Ford urged Ottawa to treat electricity, energy and critical minerals as leverage and to consider counter tariffs aimed at imports from Texas, Florida, Wisconsin and Alabama.
Hamilton Mayor Andrea Horwath, whose city accounts for roughly 60 per cent of Canadian steel output, called the breakdown “extremely concerning” for local employers before endorsing the decision later Saturday. “As a steel and manufacturing city with a significant agricultural sector, we know the uncertainty ahead will be stressful for many Hamiltonians,” she said in a statement quoted by BNN Bloomberg.
Brampton Mayor Patrick Brown tied the rejection directly to his city’s idled Stellantis assembly plant. “Stellantis made it clear to me that as long as there are tariffs, there was no business case for auto production in Canada, and they were leaving until tariffs were lifted,” he told CP24. “So, I’m glad the prime minister didn’t accept a bad deal. It would not have salvaged the auto sector in Canada.” Toronto Mayor Olivia Chow urged residents to buy local. Unifor national president Lana Payne supported the government’s position while noting that Canadian workers have already absorbed 18 months of punishment.
Business groups were considerably less enthusiastic about the arithmetic, even where they accepted the politics. Candace Laing, president and chief executive of the Canadian Chamber of Commerce and a member of the Prime Minister’s advisory committee on Canada United States economic relations, called the tariffs “a body blow to North American competitiveness in this self defeating trade saga.”
“A whopping, non absorbable tariff is not sustainable or viable for business,” Laing said in remarks reported by the Associated Press. “For a small Canadian exporter operating on tight margins, this isn’t an abstract trade dispute. It means looking at your orders, your payroll and your employees and asking what you can still afford.” Americans will see costs rise, she said, while Canadians will watch customers, investment and small businesses disappear.
Julian Karaguesian, a lecturer and trade specialist at McGill University, made the same point in blunter terms in comments to Al Jazeera earlier in the week. “Tariffs of 50 per cent would effectively price hundreds of Canadian goods out of the US market,” he said.
The economic arithmetic
A 50 per cent duty is not a margin problem. It is a market access problem. At that rate, the practical question for most exporters is not how to split the cost with a buyer but whether the sale exists at all.
The Frequency analysis published on August 22 puts the exposed export base at US$17.7 billion to US$20 billion annually, roughly C$24 billion to C$27 billion, and estimates that Canada’s trade weighted average tariff into the United States rose 1.89 percentage points overnight, from 4.68 per cent to 6.27 per cent. If volumes fall in proportion to the price shock, that analysis projects annual revenue losses above US$10 billion.
On employment, the same analysis models 52,000 direct job losses in affected sectors and 87,000 to 90,000 in total once suppliers and service providers are counted. The Hub reached a similar figure of roughly 90,000 jobs at risk in analysis published on August 20, before the duty took effect. Frequency notes that the shock lands on a labour market that had already shed more than 100,000 full time jobs in the first two months of 2026, with manufacturing taking the largest share, and on an unemployment rate that Statistics Canada had recorded climbing to a six month high of 6.9 per cent in April, driven explicitly by trade uncertainty. Layering a further 0.4 point deterioration on that base points toward 7.2 to 7.3 per cent by the fourth quarter.
The projected hit to real gross domestic product growth is more modest, in the range of 0.2 to 0.3 percentage points on an annualised basis for the remainder of 2026. Economists cited in coverage of the measure describe the macroeconomic effect as a couple of tenths off growth, which is real but survivable at the national level and considerably worse than that inside particular towns.
Retaliation adds a second, domestic price shock. Frequency estimates the September 8 countermeasures could add 0.2 to 0.5 percentage points to Canadian headline inflation, a wider range than in previous rounds because the goods in scope include everyday consumer items rather than only industrial inputs.
Set against all of this is the scale of what still works. The two countries exchanged roughly US$880 billion in goods and services last year. Nearly 330,000 people and US$2 billion of goods cross the border every day. Statistics Canada reported that close to 72 per cent of Canadian goods exports went to the United States last year. The 95 per cent of trade not covered by these proclamations is the reason the projected GDP impact is measured in tenths.
What importers and exporters should do this week
Four items belong at the top of every trade compliance list right now.
First, verify at the tariff line, not the product category. The binding text is the specific subheadings named in each of the three proclamations and reproduced in the Federal Register notices. Product category summaries circulating in the press are useful for orientation and dangerous for classification. Confirm your codes against the notices or with a licensed customs broker before assuming either coverage or exclusion.
Second, stop treating CUSMA as a shield. Origin qualification is irrelevant to this measure. If your duty calculation logic keys off a preference indicator, it is producing the wrong number as of Saturday morning.
Third, re run landed cost and re open quotes. The duty is live, not pending. Contracts priced on delivered duty paid terms with Section 338 exposure have already changed economics, and Incoterms allocation is now the difference between a thin quarter and a loss. Review force majeure and change in law clauses, and check whether duty drawback or a foreign trade zone can recover or defer any part of the charge on goods that are re exported or further processed.
Fourth, if you also sell into Canada, prepare for September 8 now. The sectors are known even though the lines are not. American steel, dairy, appliances, agricultural equipment, pulp and paper, and electronics are in scope. Buyers of American machinery and appliances have a narrow window to accelerate arrivals, and Canadian importers should be ready to file remission applications the moment Ottawa publishes a process.
What happens next
Two clocks are running. The first ends on September 8, when Canada’s countermeasures take effect and the dispute becomes reciprocal in fact rather than in rhetoric. The second has no fixed end at all: Section 338 carries no sunset, requires no periodic review, and can be lifted only by the president who imposed it.
Sitting behind both is the unresolved question of CUSMA itself. Washington has begun formal renewal talks with Mexico. It has not begun them with Canada. Greer described launching those negotiations as one of the deliverables of the package Canada rejected, which means the collapse has pushed the agreement’s renewal further out of reach rather than closer.
Ryan Majerus, a partner at King and Spalding and a former United States trade official, told the Associated Press that both governments will feel pressure to find a way out. “Canada likely wanted further sector specific relief than the U.S. was willing to offer, or Canada’s concessions did not go far enough,” he said. “Either way, I think both sides will be under immense pressure in the coming days to still find an off ramp. But if Canada has agreed to also impose tariffs, the off ramp may be even harder to find.”
Carney, for his part, has stopped describing the relationship as recoverable in its old form. Canada has recognised that “America has changed,” he said on Saturday, and the two countries will “not return to our old relationship.” His stated plan is to strengthen the domestic economy and expand trade elsewhere. “We’ve got the reserves. We’ve got the resilience,” he said.
For the exporter in Cambridge or Trois Rivieres or Prince George whose product is on the list, resilience will be measured over the next several weeks in orders retained, not in language.