Poland's President Andrzej Duda (R), NATO Secretary General Jens Stoltenberg (L) and US President Barack Obama (C) pose for a picture prior to the opening of the NATO summit on July 8, 2016 at the Belweder Palace in Warsaw, Poland. The Polish capital Warsaw hosts a two-day top-level NATO meeting, for the first time since Poland joined the alliance in 1999. / AFP / STEPHANE DE SAKUTIN (Photo credit should read STEPHANE DE SAKUTIN/AFP/Getty Images)