At a press conference at Mar-a-Lago on Tuesday, Mr. Trump escalated his talk of annexing Canada to the United States. He also reiterated his intention to impose "substantial" tariffs on Canadian and Mexican goods. Asked if he would use military force to annex Canada, he replied, "No - economic force. Because of Canada and the United States, that can really work. You can erase that artificial line and see what it looks like, and it would be much better for national security - don't forget that Canada is basically our protection." Mr. Trump claims that the United States posts as much as $200 billion a year to Canada. His claim may include other factors besides the trade deficit. The United States imports more than 4 million barrels of crude oil a day from Canada in some months. Canadian Prime Minister Justin Trudeau responded to the latest remarks by saying that it is impossible for Canada to join the United States.