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President Barack Obama, Canadian Prime Minister Justin Trudeau and Mexican President Enrique Pena Neito participate in a trilateral news conference for the North America Leaders' Summit at the National Gallery of Canada, Wednesday, June 29, 2016 in Ottawa, Canada. (AP Photo/Pablo Martinez Monsivais)

President Barack Obama, Canadian Prime Minister Justin Trudeau and Mexican President Enrique Pena Neito participate in a trilateral news conference for the North America Leaders’ Summit at the National Gallery of Canada, Wednesday, June 29, 2016 in Ottawa, Canada. (AP Photo/Pablo Martinez Monsivais)