Can Justin handle the fighting?
It's in a moment like this that it would be better for Canada's relationship with the USA to be dealt with by Stephen Harper. I can see him dealing with Trump more effectively. He wouldn't be so worried about the media in a battle like that - as will Mr. Trudeau. And Canadians would likely be very supportive. With Mr. Trudeau, I fear that he personally will be fueled by huge numbers of foreign media watching things - and put on more of a show of "charm" than anything else. If Harper was in charge of this mission, he wouldn't hesitate to stomp on America's toe if required. Trudeau himself will hesitate - wanting to "look" as good as possible as he battles the  creepy new President of the USA.