This is a summer movie that’s been seen before: President Trump makes demands. When the other side does not give him what he wants, he escalates with bombastic threats of crippling punishment. The other side surrenders.

Except that Mark Carney, the prime minister of Canada, evidently has not read the script. His refusal to buckle in the face of Mr. Trump’s trade ultimatum even at the cost of retaliatory tariffs has flipped the narrative of the president’s second term. Instead of giving in, Mr. Carney is testing whether defiance is a viable strategy against Mr. Trump.

The age of capitulation that defined Mr. Trump’s return to office may be starting to fade. World leaders and domestic institutions are, in some cases at least, showing less willingness to submit to Mr. Trump’s will. European leaders have refused to join his war with Iran.

Prime Minister Benjamin Netanyahu of Israel flatly rejected his Gaza plan. Gulf Arab states forced him to abandon plans to charge a shipping toll in the Strait of Hormuz. Universities and law firms are rebuffing his directives rather than signing on the bottom line.

Bond markets are rebelling against his fiscal policies. Even the ABC network, whose $16 million payment to settle a Trump lawsuit was seen as an early example of yielding to the president, has discovered that it did not buy peace and is now suing his administration for threatening its broadcast licenses. None of which means that Mr. Trump should be underestimated.

Although his poll numbers are at or near historic lows, he remains the most dominant figure on the planet, able to reset the terms of the global conversation on a whim with a social media post and unafraid of wielding power in ways that his predecessors did not.