President Donald Trump pulled out of trade talks with Canada Thursday night, furious over what he called a “fake’’ television ad from Ontario’s provincial government that quoted former U.S.

The 1987 radio address by the former U.S. President Ronald Reagan at the centre of a new U.S.-Canada row was a defence of free but fair trade in which he explained his decision to put duties on Japanese goods in a trade dispute.

Reagan saw tariffs as a last resort. For Trump, they are the first step to force scores of countries into high-pressure negotiations.

High tariffs inevitably lead to retaliation by foreign countries and the triggering of fierce trade wars.’