The Globe and Mail reports in its Saturday edition that the U.S. Supreme Court has upheld rulings that President Trump's use of the International Emergency Economic Powers Act to impose tariffs is unconstitutional and must end. Guest columnist Carlo Dade writes that most tariffed Canadian exports remain unaffected by Friday's ruling, which is still significant for Canada. The data show that a shared national problem will now become more fragmented and regional. The shift in U.S. tariffs will necessitate new policy approaches in Canada, with varying provincial responses to meet both domestic and U.S. needs. The U.S. Supreme Court faces a complicated question: Has Congress delegated its tariff-imposing power to the President, effectively abdicating its responsibility? The President now has the ability to impose tariffs on any item, for any amount, duration or reason, by declaring an international emergency, a definition he alone controls. Worse, the ability to credibly threaten to impose tariffs at will does more damage than the actual tariffs. Mr. Dade argues that a fixed tariff is manageable, but an unpredictable one creates uncertainty that undermines a business's ability to adapt and is more damaging.