In 2017, when our fresh-faced prime minister was still under the mistaken impression that incessant virtue-signalling was a reasonable way to run a country, Justin Trudeau issued a proclamation to the world’s huddled masses: “To those fleeing persecution, terror & war, Canadians will welcome you, regardless of your faith. Diversity is our strength #WelcomeToCanada.” Canada, in other words, was instituting an open-door immigration policy, in contrast to the United States, where president Donald Trump had just signed an executive order intended to curb Muslim immigration.