Everyone is fixating on what the Russian Candidate is saying without reading what the article says. As I read it the US Congress and Senate have 90 days to give him authorization to renegotiate NAFTA. After that talks can begin. Negotiations are likely to take months. 

He may want a quick deal but the only way he will get one is if he threatens to withdraw from NAFTA and  Mexico and Canada both cave in to his demands. That is doubtful. If he does pull out of NAFTA there will be serious  recriminations. Failing to come to a deal with  its immediate neighbours will be a huge embarrassment for the US.

The Russian Candidate cannot afford to lose this fight and the US cannot afford to lose face because it has much bigger trade issues with China. If the Russian Candidate cannot win on his home turf  he  stands no chance anywhere else.

I expect legislators will put him on a short leash.