Trump continues his tiresome practice of mixing implied threats with implied suggestions that reasonable accommodations are possible.  Canada and Mexico need to ignore this one man Greek Chorus and maintain a fact-based, firm but reasonable focus throughout these negotiations.

If Trump renews his threats of withdrawal from NAFTA if his demands are now accepted without reasonable compromise and reciprocity, then Mexico and Canada (and the peoples of both countries) need to be prepared to suspend negotiations until such threats are withdrawn.

There are many interests in the US that will act to thwart US withdrawal from NAFTA in such circumstances.  If we're firm but reasonable a reasonable, balanced reform of NAFTA is possible but Canada and Mexico will be tested throughout by Trump's temptation to bully.