NAFTA is the same agreement for 3 countries, same wordings. But only the U.S. blames it for its troubles. The blame lie with U.S. implementation, not the agreement. Their law-makers chose to run NAFTA solely to benefit the corporations, by deregulating them, by not taxing them for their enhanced profits. 

Trump is playing the blame game on trade. He wants to change NAFTA, not Mexico or Canada.  It's up to him to submit his complaints. If we agree there is substance we can decide to negotiate. Else we walk. It's up to him to either withdraw his complaints or withdraw from NAFTA. 

If Trump decides to withdraw he faces his people with all the consequences. Let him tell Americans they will have more and better jobs without NAFTA. 

If Ottawa decides to negotiate, the modified agreement, or a completely new agreement, MUST be approved by the people via election or referendum. Ottawas today does not have a NAFTA mandate.