(Bloomberg) -- Donald Trump’s campaign promise to hike import tariffs could trigger retaliation from other nations including trade partners, Canada’s ambassador to the US warned.

Ambassador Kirsten Hillman said in an interview Friday that Canada thinks the US-Mexico-Canada Agreement for free trade, negotiated during Trump’s first term, should exclude it from his plan to impose 10% duties on goods from around the world if he’s elected to another term in November. Chinese imports would face a 60% tariff.

“It’s not a one-way street — other countries, if that policy is enacted, will respond,” said Hillman, who helped negotiate the USMCA. “That could potentially raises costs for everybody.”

A second Trump White House should expect trade partners to respond with reciprocal tariffs, as they did for duties on steel and aluminum that Trump imposed in his first term, Hillman said. Canada, the US and Mexico negotiated the USMCA at Trump’s insistence to replace the two-decade-old North American Free Trade Agreement, which he blamed for the loss of US manufacturing jobs.

Although Trump threatened at one point to end free trade in the region altogether, the nations fashioned a deal that won broad bipartisan support in the US Congress. They’ve since focused on deepening integration, especially in critical industries like semiconductors, after the disruption of the Covid-19 pandemic. 

Hillman, who previously worked as a trade lawyer and negotiator, said she doesn’t see the world breaking down into rival trade blocs even though she agreed that returning some supply chains to the region for critical inputs like food and energy makes sense. 

Hillman downplayed concerns about a USMCA review scheduled for 2026, calling it an opportunity to improve the deal rather than renegotiate it.

With the US election looming, Hillman said Canada continues to use its network of consulates to establish relationships nationwide with both Republican and Democratic lawmakers and aides.

Hillman added that she’s been in touch with some Trump advisers since he left office.

“Obviously, that’s deeply important, in order to get as much information as we can from every region to inform ourselves as to what’s happening under both potential outcomes after the next election,” she said.

--With assistance from Josh Wingrove.

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