NYTWAS 30191750A/30192255A-ANDREWS AIR FORCE BASE, MD–June 29, 2016-With Parliment Hill as a back drop, President Enrique Peña Nieto of Mexico, Prime Minister Justin Trudeau of Canada and President Barack Obama pose for a “leader” photo during the North American Leaders Summit in Ottawa, Ontario. photo by STEPHEN CROWLEY/THE NEW YORK TIMES NYTCREDIT: Stephen Crowley/The New York Times