alt Hacker NewsA few months prior to the midterms is exactly the right time for this sort of action. If the voters keep seeing prices increase because of Trump's tariffs, it increases the odds that the republicans will lose the legislative branch and will be able to act as a check on Trump's power. Ideally some other countries will follow suit.
This will cause some short term pain for Canada, but hopefully they'll have a less insane trading partner after November.
Unfortunately I think the only usable big lever we have as Canadians -- wine/beer liquor imports and people choosing to restrict personal travel to the US -- has already been used. We cannot and will not exercise energy or potash restrictions. And import tariffs are unlikely to be substantially impactful enough for Americans to notice enough that it alters their decisions at the ballot box.
I would however urge my fellow Canadians to continue to or start boycotting goods from the US and travel to there, generally.
And likely encourage Americans to come visit here. Come ski here this winter. You're more than welcome here.