The U.S., Canada and Mexico signed a new trade deal championed by President Donald Trump to replace the quarter-century-old NAFTA pact, capping a year of intense negotiations and offering a glimmer of certainty amid rising global tensions over trade. Trump, Canadian Prime Minister Justin Trudeau and outgoing Mexican President Enrique Pena Nieto signed an authorization for the deal on Friday morning in Buenos Aires on the sidelines of the Group of 20 summit, with their ministers signing it shortly after.