We'll see. With the latest spat with China, Trump announced sanctions and then, almost immediately, frantically negotiated and conceded his way back to more or less the same position he started at. Apparently a single San Diego factory was at risk of closing, and local Republicans complained.
Canada, believe it or not, has even more leverage over the US than China. It is the number one export market for 35 US states, something which Canadian representatives have been making very clear to each and every governor over the last few months. Moaning about the United States is almost the only thing that makes Canada approach coherence as a country, and standing up to the evil USA is the stuff even the most mediocre Canadian politicians have built decades-long careers from.
I expect Trump will fold at the first hint of any real pressure, just as he's done virtually every other time he's shot his mouth off and ended up in trouble. There is very little real constituency for any of this, and the rest of the world has a lot of experience dealing with America's periodic trade tantrums. Lamy eviscerated Bush back in 2003, for instance.
