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.

The Canadian PM responds firmly as the president proposes a "wonderful marriage" of incorporating Canada into the US.

A meeting between the leaders of Canada and the United States is not usually considered a high-stakes showdown, but there was little ordinary about this one. Here was newly elected Prime Minister Mark Carney making his first visit to the Oval Office to see President Donald Trump,