The Globe and Mail reports in its Tuesday edition that the collapse of trade negotiations in Washington last week was unsurprising because of unacceptable United States demands that emerged in the final hours. Guest columnist Lawrence Herman writes that Prime Minister Mark Carney made the right choice by ending the talks and confirming that Canada will retaliate dollar for dollar, reflecting the nation's strong resolve. Mr. Herman believes there are important lessons from recent blunders in dealing with President Donald Trump that must not be repeated as we prepare for future challenges. The most serious strategic error was entering these negotiations in the first place. Once Mr. Trump threatened these latest 50-per-cent tariffs, resurrecting the discredited 1930 Smoot-Hawley Tariff Act, Canada should have refused further trade talks. Coming to the negotiating table with an unconscionable threat like this looming over the process was unwise. Ottawa should have immediately said it would take countermeasures of its own if these tariffs came into effect. Of course, we've now done just that -- but announcing them last month, Mr. Herman says, would have been more effective. It might have torpedoed negotiations.