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The Detroit skyline in 2023. Detroit and Windsor, Ont., share a river, a border and a reliance on the auto industry.Fred Lum/The Globe and Mail

Ontario’s Ronald Reagan ad campaign enraged a mercurial American President and torpedoed trade negotiations between Canada and the U.S.

But just across the river from Windsor, Ont., in Detroit, not everyone has noticed the 60-second TV ad that has chilled diplomatic relations with Canadian neighbours they’ve always considered family.

Pausing his bike ride to take a selfie with Caesars Windsor Hotel & Casino in the background, Mike Johnson said he hasn’t seen the clip.

“I watch Channel 4, Channel 7, subscribe to the Detroit Free Press, Detroit News, Wall Street Journal and I still have not seen these ads,” he said. “Read some stories about them. But haven’t seen them.”

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Mr. Johnson and other Detroiters consider Windsor less a foreign country and more a neighbourhood of their own city, sometimes referred to as South Detroit. The cities share a river, a border and a reliance on an auto industry that moved product freely until U.S. President Donald Trump introduced tariffs this year.

The Reagan ad campaign, originally budgeted at $75-million, ran throughout the United States before it was pulled off the air earlier this week. It features audio of a radio address that Mr. Reagan gave in 1987 in which he explains why he opposes most tariffs.

“High tariffs inevitably lead to retaliation by foreign countries and the triggering of fierce trade wars,” he said. “Then the worst happens. Markets shrink and collapse. Businesses and industry shut down, and millions of people lose their jobs.”

The Ronald Reagan Presidential Foundation complained that the ad misrepresented the former president’s comments. Mr. Trump went further, declaring the ads “FAKE” on Truth Social and falsely asserting the spot was generated by AI.

Kathy Kay from Detroit says the President is the one misrepresenting the situation.

“He didn’t listen to the whole thing,” she said, walking at a brisk pace along the Detroit River. “Ronald Reagan was saying we didn’t need tariffs. That man in office, I won’t say his name, is the one misrepresenting.”

Ms. Kay admitted she hasn’t seen the ad herself, just coverage of the ad on MSNBC.

“Who pays for tariffs? We do, the consumer,” she said. “Prices are up.”

On Wednesday, General Motors announced around 3,300 layoffs in the U.S., primarily among factories geared to electric vehicle production. Inside the company’s world headquarters in Detroit, the eerily vacant Renaissance Center, a dozen or so people were keeping warm among empty storefronts and closed fast-food outlets.

One man, William Smith, said he’s heard about “this beef with Canada.”

“I don’t know what good it’s doing anybody,” he said.

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In Troy, a northern suburb of Detroit, the sentiment was different. Outside the Oakland Mall, several people said they had seen the entire ad on conservative networks.

“It was really dumb to run that ad at this time,” said Tony Dimambro. “And it was misleading. Reagan was in favour of some tariffs.”

Mr. Dimambro said half his family lives on the other side of the border. He feels for any economic pain Canadians are feeling, but supports the tariffs as a way of bringing jobs back to the U.S.

“When it comes to Trump, I love his policies but I hate his personality and his mouth,” he said.

The ad ran on major U.S. networks, including during major sporting events.

Sandra Jones recalled seeing the ad several times but couldn’t remember whether it was during a sports or news broadcast. “I’m not your typical grandma,” she says, a Detroit Lions pin shining on her shirt. “I watch Fox and sports.”

She faulted Ontario for airing an inflammatory ad during a sensitive stage of trade negotiations. “It wasn’t right and it really backfired,” she said. “It’s pushed Trump and your Prime Minister apart.”

While Mr. Trump seems to have soured on Canada, Ms. Jones has not.

“I’m really pulling for those Blue Jays,” she said.