US is in for a reset. Not sure how this will effect everyone else but needless to say they will not be able to be counted on for a while, maybe a long while. Individual states with their shit together and that are close to Canada's border are mostly on the West Coast. Ontario's closest trading partners by land won't have their shit together and will probably act as intermediaries for states like Idaho who I hope will continue to run smoothly enough.
International trade won't stop without great complications, of which there have been many in recent years. Port backlogs, strikes and cyber-attacks could prove catastrophic if occur while the US fed is paused.
I don't expect depression'esque shortages but extreme delays with high money velocity as the public gets spooked by empty shelves.