US President Barack Obama (R) and British Prime Minister Theresa May arrive for a press conference on the sidelines of the G20 summit in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / SAUL LOEBSAUL LOEB/AFP/Getty Images