I certainly agree with you that Mulroney will - and already has - provided much more valuable counsel on NAFTA, Canada-US relations and the president and the commerce secretary than Butts possibly could.

But for the record, the invitations to Mulroney and Burney were extended by Marc Garneau the chap who was actually qualified to be PM but lost to the selfie-made man with the famous name and luxuriant hair in 2013.  (It was the triumph of the space cadet over the space man.)

You see, the arrival of Trump forced Trudeau to shuffle his cabinet and actually put in a few qualified ministers and Garneau who was already transport minister was give the added role of chairing the select cabinet committee on Canada-US relations.  So it was Garneau who invited these chaps. 

Trudeau won't even be there.  He'll be doing what he does best - in New York at a womens' opportunities conference, posing for selfies and reading ghost written feel good speeches.