McKenna does not seem to know that financial trade and climate problems are totally separate.
Most people are aware that the USA is a major polluter, as is China and India , and possibly Brazil, and maybe Mexico. 
Therefore all of these countries should be included in the NAFTA talks,...or..... stop the stupidity.   McKenna is a fool, and is hurting Canada at the negotiating table.   McKenna Freeland and Trudeau seem to be only concerned with voter appeal.  
Want to appeal to voters?  Drop the Carbon Tax.