Canadian Prime Minister Justin Trudeau said Monday that Americans “are beginning to wake up to the real reality that tariffs on everything from Canada would make life a lot more expensive" and said he will retaliate if Donald Trump goes ahead with them.

The president-elect’s mockery of Canada and its leader is the latest salvo after his promise to impose steep tariffs on Canadian exports.

The threat of tariffs has put pressure on Canada to clamp down on illegal crossings into the U.S., even as some Canadian officials anticipate a surge in migrants heading the other direction once President-elect Donald J. Trump takes office. ALBANY — For most of the 20th century, the world’s longest international border was practically undefended.