WARSAW, POLAND - JULY 8: Alexis Tsipras, Prime Minister of Greece, arrives for the Warsaw NATO Summit on July 8, 2016 in Warsaw, Poland. (Photo by Dursun Aydemir/Anadolu Agency/Getty Images)
WARSAW, POLAND - JULY 8: Alexis Tsipras, Prime Minister of Greece, arrives for the Warsaw NATO Summit on July 8, 2016 in Warsaw, Poland. (Photo by Dursun Aydemir/Anadolu Agency/Getty Images)