this is a non-starter and, frankly, a dumb idea.
what would happen, instantly, is that everybody would sell all of their canadian dollars for us dollars, thereby crashing the currency. we'd just all end up using american money. that's not going to help american manufacturers, either, as they'd lose their advantages in economies of scale.
do you know what policy would actually succeed in getting what donald trump wants? he'd have to invade and occupy mexico and canada. nothing else is going to get him what he wants.
don't tell him that, though.
it's becoming increasingly clear that canada is best off ripping up the deal and waiting for the next president to renegotiate. let's not forget that this is an option: we could always just sit still and wait for him to die.
http://globalnews.ca/news/3458565/nafta-trade-deal-currency-clause/