US bans Canadian spirits and dairy from 29 September
Washington's import ban lands three weeks out. Canada's retaliatory duties on US steel, clothing and furniture are already live. Small importers on both sides now have a diary date and no tariff codes to plan against.
The United States will bar a range of Canadian goods from entry starting 29 September. The list announced on Tuesday covers alcoholic spirits, dairy products including whey, and motor vehicles.
The measures came in a series of executive orders. The White House said Canada is "discriminating" against US businesses by restricting the distribution of American goods while leaving comparable products from other countries alone.
Canada's counter-tariffs took effect after midnight on Tuesday. They hit US steel, clothing and furniture, and were set dollar-for-dollar against the American duties that preceded them.
Those American duties came last month: 50% tariffs on around $20bn (£14.8bn) of Canadian goods, imposed after several rounds of talks broke down. They covered furniture, wine, and sporting and fishing equipment.
For a small importer, the difference between the two instruments matters. A tariff makes a shipment more expensive. A ban stops it at the border, which means no landed cost to recalculate and no margin to protect — only stock that cannot move.
That is the immediate problem for anyone selling Canadian spirits into the US market direct to consumers. Orders placed now against September delivery are exposed to a cut-off date already on the calendar.
The announcements named product categories rather than tariff lines, so importers cannot yet match a specific customs code to the ban. Anyone whose goods sit near the edge of "dairy" or "spirits" has three weeks to find out from a broker whether they are inside it.
The exposure is lopsided. More than two-thirds of Canada's total exports generally go to the United States, its largest trading partner. Canada is the second-largest trading partner of the US, after Mexico, and its export base is far more diversified.
Prime Minister Mark Carney said in a video address on Tuesday that his country's pivot away from the US as its largest trading partner "will come at a cost". His office had not commented on the new import ban at the time of the BBC's report.
Officials on both sides say they want a trade deal. No new talks have been scheduled since negotiations collapsed in late August.
There is also a signal about what comes next. On Monday, Trump warned the Canadian aircraft maker Bombardier that it would lose access to the US market unless it moved manufacturing there.
Business owners on both sides of the border have said they expect prices to rise and customer numbers to fall.
The practical reading for a founder shipping across this border: treat 29 September as a hard stop rather than a negotiating position, get a customs broker to confirm which of your SKUs fall inside the named categories, and assume the category list can grow. The Bombardier warning suggests the mechanism now being used is market access, not price.