It's Wednesday 18 June in Ottawa, and Canada's Minister of Finance François-Philippe Champagne is scurrying into the elegant lobby of the Château Laurier, a luxury hotel just a few steps away from the national parliament.

He has good reason to be hasty. In the wake of a G7 summit held in the west of the country under the leadership of Prime Minister Mark Carney and from which US President Donald Trump made an abrupt exit, the Quebec minister has been summoned to take charge of the thorny issue of