It strikes me that Canada made significant concessions to reach the original NAFTA agreement. These included issues, such as intellectual property, that have been extremely favorable to the US - I would note that the US patent system enables American businesses to harass competitors using questionable patents on a tilted legal playing field (and I can assure you that, in my professional field, I have noticed that many patents should never have been issued -they basically recycle ideas that have been around for decades).

Our negotiators should be well prepared to remind their counterparts of this. They should also be ready to make the point that the credibility of the US as an economic/business partner is at risk.