Donald Trump keeps insisting that the borderline between the U.S. and Canada is "artificial." It's worth asking why he's become fixated on this.

Canadian Prime Minister Mark Carney visited the White House on Tuesday for his first talks with Donald Trump and bluntly told the U.S. president that Canada would never be for sale.

Carney has taken a defiant stance against Donald Trump, vowing that Canada will never become the 51st US state, despite repeated threats from the US president. The highly anticipated meeting between the two leaders today will hopefully provide a clearer indication of what direction their relationship will take.