Let's say Mr. Trump does try to pull NAFTA, but it turns out Congress has the power.

As mentioned elsewhere in the Globe, the original Canada-US Free Trade agreement will come back into force - on terms more advantageous to the United States.

That will give Trump the opportunity to campaign AGAINST free trade with Mexico. 

Now, I may be wrong, but in the USA, politically taking a stand for free trade with Mexico is taking a stand on quicksand.

It's a winning hand for Trump, whether he has the power to withdraw or not.

Moreover, I don't think the Liberals would be so foolish as to abrogate free trade with the United States because the Trump leaves an agreement with Mexico.  Or think they can bluff Trump into NAFTA.

Really, Trump has Clint Eastwood's "make my day" line.  (Really, Mr. Martin?  Justin Trudeau is now Dirty Harry?  Good gravy.)