Trade wars with allies could spiral as the president tries to get trading partners to back down from retaliation with new threats of his own.
For the second time this week, President Trump has threatened to disrupt trade with a close ally for retaliating in a trade war that he started — a tactic that could lead to compromise, or to economic spats that spiral further out of control.
On Thursday morning, Mr. Trump tried to cow the European Union into submission, threatening in a social media post to put a 200 percent tariff on European wine and Champagne unless the bloc dropped a 50 percent tariff on U.S. whiskey. The European Union had imposed that tariff in response to levies that Mr. Trump put on global steel and aluminum on Wednesday.
Mr. Trump deployed a similar tactic against Canada on Tuesday, threatening to double 25 percent tariffs on Canadian steel and aluminum to try to get Ontario to lift a surcharge on electricity sold to the United States. The province had imposed the charge after Mr. Trump put other tariffs on Canada this month.
After Ontario suspended its surcharge, Mr. Trump walked back his threats.
Over the last several weeks, Mr. Trump has presided over a confusing and potentially economically devastating back and forth of tariffs and tariff threats, playing a global game of chicken as he tries to get some of the United States’ closest allies and trading partners to back down.
Mr. Trump has wielded the tariff threats without regard for their economic consequences and, increasingly, seemingly without regard for the impact on stock markets. The S&P 500 slumped again on Thursday after Mr. Trump threatened Europe and reiterated at the White House that he would impose big tariffs.
When asked whether he might relent on Canada, which sent a delegation to the United States on Thursday to try to calm trade tensions, Mr. Trump said: “I’m not going to bend at all.”