Here's a tweet from Daniel Dale of the Toronto Star:
Trudeau says he wanted to meet with Trump to resolve NAFTA, but Pence told him that he couldn't meet with Trump unless Canada accepted an auto-termination "sunset clause" in the deal. He said Canada could never accept a sunset clause in NAFTA. Meeting never happened.
A lot of so-called "poison pills" have been discussed in the context of the NAFTA renegotiation. Some big ones are: The sunset clause, an ISDS opt-out, eliminating Chapter 19, weakening Chapter 20, gutting government procurement liberalization, and certain US proposals on auto rules of origin. On everything but sunset, I can imagine an overall package where the U.S. gets some of what it is asking for. But with regard to the sunset clause (usually described as NAFTA expiring in 5 years unless each government -- in the U.S., the President -- agrees to continue it), there is no way this will happen. Canada and Mexico will not agree to it, and even if they did, Congress would not agree to it. Congress would not want to shift this power to the Executive (and would not want to exercise this power itself).
So if the Trump administration is that determined to get a sunset clause, where does that leave us? Unfortunately, not in a very good place. They can get some of the other things, for better or worse. But if this is really what they want, we are in for a bumpy ride in the coming weeks and months.