Talks Collapsed, Tariffs Are Live: What the U.S.-Canada Trade War Means for Your Shipments

For a few days last week it looked like Washington and Ottawa might pull off a last-minute deal. They didn't. Trade talks between the United States and Canada collapsed late Friday, August 21, and just after midnight the U.S. imposed 50% tariffs on roughly $20 billion worth of Canadian goods. Canadian Prime Minister Mark Carney responded almost immediately, promising to match the U.S. tariffs "dollar for dollar" starting September 8. For importers and exporters doing business across the northern border — or anyone whose supply chain touches Canada — this is no longer a hypothetical. It's live.

What actually happened

The tariffs were originally slated to take effect August 19 under Section 338 of the Tariff Act of 1930 — a Depression-era authority the administration invoked for the first time this year after the Supreme Court struck down IEEPA-based tariffs back in February. The White House postponed the effective date twice to allow negotiations to continue, most recently pushing it to August 22. When Canada declined to finalize a deal on the terms the U.S. offered in the final hours, U.S. Trade Representative Jamieson Greer announced the tariffs would proceed. They took effect just after midnight Saturday.

The Section 338 duties apply to about $20 billion of Canadian exports — roughly 5% of what Canada ships to the U.S. annually — covering goods including wine, furniture, dairy products, cement, clothing, fishing rods, and hockey equipment. Critically, this batch of tariffs does not get a USMCA exemption; goods that previously cleared duty-free under the USMCA preference are now fully exposed if they fall within the covered categories. Section 338 tariffs also don't stack with Section 232 sectoral tariffs (steel, aluminum, energy, critical minerals, fish, potash) or aerospace — so goods already paying those duties are carved out of this new layer.

Canada didn't wait long to respond. Carney announced Saturday that Canada will impose its own retaliatory tariffs starting September 8, targeting U.S. exports including steel, dairy, appliances, agricultural equipment, paper, and electronics — described as a "dollar for dollar" match. No further U.S.-Canada talks have been scheduled, and the breakdown casts real doubt on USMCA renewal negotiations with Canada, even as the U.S. presses ahead with separate talks with Mexico.

What it means for importers

If you bring in Canadian-origin goods that fall into the newly tariffed categories, your landed cost just went up 50% on that portion of your supply chain — and your existing USMCA certificate of origin won't shield you from it. That changes the math on sourcing decisions that may have made sense a month ago.

• Confirm your HTS exposure. Pull your Canadian-origin import lines and check which HTS codes fall under the Section 338 list. Don't assume USMCA coverage protects you — for these specific goods, it doesn't.
• Check for tariff stacking conflicts. If you've been paying Section 232 duties on steel, aluminum, or other covered inputs from Canada, verify which authority now governs those entries — Section 338 and Section 232 aren't meant to stack, but getting the classification wrong means overpaying or underpaying.
• Look at Foreign Trade Zone options. Goods admitted into an FTZ under privileged foreign status can still access relief under Section 338 — worth a serious look if you're carrying Canadian inventory domestically.
• Get ahead of September 8 if you export to Canada. If your business ships steel, dairy, appliances, agricultural equipment, paper, or electronics north of the border, Canadian retaliatory duties hit those categories in about two weeks. Talk to your Canadian buyers now about who absorbs the cost, and consider whether shipments can be timed to clear before the deadline.
• Don't count on a quick reversal. Both governments have now publicly committed to their positions, which trade lawyers are calling harder to walk back than the usual tariff brinkmanship. Plan for these duties to be in place for a while, not days.

The bigger picture

This is happening against a backdrop where de minimis treatment remains suspended for all countries, USMCA renegotiation with Canada is effectively stalled, and separate USMCA talks are only moving forward with Mexico. For South Florida importers who route through the Port of Miami with any Canadian-linked supply chain — whether that's direct sourcing or components that transit through Canada — this is one more layer of complexity to plan around before Q4 shipping schedules lock in.