Canada and Mexico appear to have reached a conclusion that when President Donald Trump threatens to withdraw from NAFTA, it is a negotiating ploy that is all bark and no bite.Trump flashed his signature bravado at a rally in Phoenix on Tuesday night when he said the United States will “probably end up terminating NAFTA at some point.” The warning shot marked the president’s first comments on the trilateral trade deal since the three countries formally began renegotiating it last week.