Great upside/downside overview. Thanks for this.  Wish I was a fly on the wall in the Calgary meeting room:

"Okay, what's the worst-case scenario Canada could accept and shake hands?"
"If it goes beyond that "worst-case," what options do we have--everything on the table, guys."
"Does the 'worst-case' scenario actually give us leverage; some advantages...if so how and where?"
"Under what circumstances--given the downsides--do we simply just cancel NAFTA entirely and get up and walk from the table?"
Stay tuned...