If President Trump's tariffs against Canada take effect, Canadian Prime Minister Justin Trudeau said the U.S. would immediately face a raft of countermeasures on Tuesday. Why it matters: Trump's comments Monday that he would impose 25% tariffs on Canada and Mexico sent markets sliding amid fears it could start a trade war,

King Charles is the head of state in Canada, which is a member of the British Commonwealth. He has come under criticism for being silent about Trump’s threats.

Canada will impose 25% tariffs on C$155 billion ($107 billion) worth of U.S. goods from Tuesday if U.S. President Donald Trump's administration follows through with its proposed tariffs on Canadian goods,