On Thursday, President Trump declared an end to trade talks with Canada, pointing to an advertising campaign that highlighted former President Ronald Reagan’s cautionary words about the potential dangers of tariffs during ongoing trade tensions between the U.S. and Canada.

In a message on Truth Social, Trump accused Canada of using the advertisement to meddle in an upcoming Supreme Court case that will decide his authority to enforce broad tariffs on foreign nations.

“Tariffs play a crucial role in safeguarding the national security and economic interests of the U.S.A. Due to their outrageous conduct, ALL TRADE TALKS WITH CANADA ARE NOW TERMINATED,” Trump announced.

Ontario Premier Doug Ford, who has frequently been at odds with Trump, initiated the ad campaign earlier this month. The advertisement features a segment from a 1987 speech by Reagan, where he discussed tariffs placed on Japanese imports and warned that prolonged trade conflicts are detrimental to consumers.

In the ad, Reagan states, “High tariffs inevitably provoke retaliation from other countries, igniting intense trade wars. The worst outcomes follow: markets contract and collapse, businesses and industries fail, and millions face unemployment.”

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.”