But at its end, no one offered any insight into what it may have achieved.
During his first presidency, Mr. Trump did slap tariffs on exports of aluminum and steel from Canada, Mexico and the European Union on ostensible national security grounds. Mr. Trudeau’s government eventually negotiated those duties away, although not without a brief period during which Mr. Trump reimposed the aluminum levy.
This week, as is often the case with Mr. Trump, skepticism emerged about whether he would follow through with his plan to introduce the tariffs, along with 10 percent duties on China, during his first day in office, Jan. 20.