How Prime Minister Justin Trudeau is responding to U.S. president-elect Donald Trump's threat to use "economic force" to annex Canada; and the potential lengths Trump will go to take control of the Panama Canal and Greenland. Also, the worries about foreign interference in the search for Trudeau's successor; and how much of a difference would a new leader make for the Liberal party? Plus, why Meta is dumping fact checkers, and how they'll be replaced.