Polish President Andrzej Duda and NATO Secretary General Jens Stoltenberg attend a press conference during the Warsaw Experts Forum prior to the official opening of the NATO summit in Warsaw, Poland, Friday, July 8, 2016.

Polish President Andrzej Duda and NATO Secretary General Jens Stoltenberg attend a press conference during the Warsaw Experts Forum prior to the official opening of the NATO summit in Warsaw, Poland, Friday, July 8, 2016.

Polish President Andrzej Duda and NATO Secretary General Jens Stoltenberg attend a press conference during the Warsaw Experts Forum prior to the official opening of the NATO summit in Warsaw, Poland, Friday, July 8, 2016.

Polish President Andrzej Duda and NATO Secretary General Jens Stoltenberg attend a press conference during the Warsaw Experts Forum prior to the official opening of the NATO summit in Warsaw, Poland, Friday, July 8, 2016.