Big diplomatic mistake. Regardless of their ideological differences, if Trudeau was older and wiser (and invited?), he would attend so that he can size up the autocratic oligarch first hand. Canada has been in the neo conservative's cross hairs since 2001 bu now it's taken a darker turn since the high end dregs and thugs have muscled into power in the U.S.. Trudeau will end up being treated like Trump's shoeshine boy, instead of,  the prime minister of Canada.