On Thursday, President Trump announced the cessation of trade talks with Canada, pointing to an advertising campaign that highlights former President Ronald Reagan’s cautions about the long-term consequences of tariffs, amid ongoing trade tensions between the U.S. and Canada.

In a Truth Social post, Trump accused Canada of using the ad to “interfere” with a pending Supreme Court case that will decide his authority to enforce comprehensive tariffs on foreign nations.

“Tariffs are crucial to the national security and economic well-being of the U.S.A. Due to their outrageous actions, ALL TRADE NEGOTIATIONS WITH CANADA ARE HEREBY TERMINATED,” Trump declared.

Earlier this month, Ontario Premier Doug Ford, who has frequently sparred with Trump, launched the ad campaign. The advertisement includes a clip from Reagan’s 1987 speech addressing tariffs on Japanese imports, cautioning that prolonged trade conflicts harm consumers.

“High tariffs inevitably lead to retaliation by foreign countries and the onset of fierce trade wars. Then the worst happens,” Reagan states in the ad. “Markets shrink and collapse, businesses and industries shut down, and millions of people lose their jobs.”

Trump in August announced a 35 percent tariff on all Canadian goods, though products covered under the 2020 U.S.-Mexico-Canada trade agreement were exempt.

Canada is one of the United States’ top trading partners, and their economies are heavily intertwined when it comes to certain products. But Trump has repeatedly argued the U.S. does not need Canadian goods, and that Canada is far more reliant on America for its economy.

Canadian Prime Minister Mark Carney visited the White House earlier this month, where he and Trump discussed trade. 

“There’s still great love between the two countries, but you know American people want product here, they want to make it here,” Trump said during the meeting. “We are competing for the same business. That’s the problem.”