As Trump threatens tariffs against Canada and Mexico, here are five things we know so far

President-elect Donald Trump is vowing to impose tariffs of 25 per cent on all goods coming from Canada and Mexico on his first day back in the White House, until the U.S.’s two neighbouring countries stop all migrants and fentanyl from entering the nation.

Mr. Trump made the announcement at 6.35 p.m. Monday on his Truth Social platform, firing an opening salvo in the global trade war that he has long promised in his second term as U.S. president.

“As everyone is aware, thousands of people are pouring through Mexico and Canada, bringing Crime and Drugs at levels never seen before,” the president-elect wrote. “On January 20th, as one of my many first Executive Orders, I will sign all necessary documents to charge Mexico and Canada a 25% Tariff on ALL products coming into the United States, and its ridiculous Open Borders. This Tariff will remain in effect until such time as Drugs, in particular Fentanyl, and all Illegal Aliens stop this Invasion of our Country!”

For Canada, which sends more than 77 per cent of its exports to the U.S., the tariffs would represent an economic blow and threaten a recession, with the oil and auto industries particularly affected. For U.S. consumers, who would pay the cost of the tariffs, they would mean punishing inflation.

For Mr. Trump, the tariffs combine two of his foundational political issues: building protectionist trade barriers around the U.S. economy and hardening the country’s borders against migrants.

Much, however, remains unclear: whether Mr. Trump will actually be able to impose the levies, how specifically Canada and Mexico will satisfy his demands and how all of it will be bound up with his promised renegotiation of the U.S.-Mexico-Canada Agreement that governs continental trade.