Whether you consider it an odd joke, a national security threat or a negotiating tactic, Trump’s mentions of the United States annexing Canada have become a sticking point for the president, and a mystery to everyone else.And, check out The Post’s coverage of second lady Usha Vance’s trip to Greenland, which comes as Trump vows to acquire the island “one way or another.”Today’s show was produced by Ariel Plotnick with help from Emma Talkoff. It was edited by Maggie Penman and mixed by Sean Carter.Subscribe to The Washington Post here.