I'll say this , it would be foolish to ' not surmise' that Trump's invective towards NAFTA would have a negative effect on the Canadian Auto industry. If his tweets can cause manufacturers like GM, Ford and now Toyota to lose billions of dollars on the equities market, quickly I may add, then we're not very didlgent are we? If I'm running a company that manufacturers or supplies auto parts to the U.S. then I'm very nervous where Trump may go next. 
Even if Trump is unable to blow up NAFTA, the fallout from his rhetoric could be devastating for investment in this country. That's not tabloid journalism. It's merely preparing for unintended consequences. I'm not optimistic for the Canadian auto industry. I hope I'm wrong.