At some point you have to stop the hemorrhaging of jobs that has taken place since the drafting of NAFTA. The last I have heard is that because of all the manufacturing jobs that have left the country we now have an unemployment rate of 85 million jobs, and that does not include the hard core unemployed people that have stoped looking for work. If things keep going the way they are and America fails how long do you think Canada can stand alone?
The hemorrhaging of jobs has been going on for over 20 years like you pointed out earlier. The reality is that those jobs are gone to the economies that can pay workers far less to produce the same product. i.e. China... it wouldn't be any different if it was Canada, France, England, Australia, on and on. The only jobs are that are "safe" are the jobs that can't be exported, and that goes for all of the same countries that I just mentioned too. Everyone likes to try and point out that Canada is protected by the U.S. I have never agreed with this for one simple reason. Our economy is a resource based economy and as long as Canada is willing to trade freely with ALL of the countries of the world, our sovereignty is safe. The moment that we say that ALL of the resources are ours and everyone can go hump a goat, then we'll have problems. Canada is an open nation to trade with any nation who is going to treat us fairly and with respect... how long would it take for China to decide that it should come lend a hand to Canada if the American government decided that it wanted to play hard ball?... the same goes for England, France, Russia, Japan, Australia, all of Canada's trading partners. China doesn't have to come and take over Canada, China just has to come over and ensure that the trade that they want to have with Canada continues... it's called World Trade.
Americans have to face it, many of those jobs that are gone won't return, because the economic realities in the world today. Whenever, you are trying to compete with cheap labour, with low overhead, you're bound to loose. That is exactly why Canada couldn't compete with the U.S. for manufacturing... our winters for much of the country automatically drive the overhead high enough that the product was more expensive to produce in Canada as compared to the U.S., so there was no market for it.
I can afford to buy Red Wing boots. $300.00 a pop here. But the last time I went to a Red Wing store, the shoes I bought were made in China... and still $180.00. I can tell you one thing, that won't happen again... I'm just as money conscious as the next guy and we all have our priorities to satisfy.
Always remember, that "I" am going to be the happiest guy around if Trump walks out and kills NAFTA, I didn't want it then, I don't want it now, and the moment that NAFTA is killed, it will do ZERO to help the American Government re-coup jobs THAT HAVE GONE OVERSEAS.