US President Barack Obama (R) and Polish President Bronislaw Komorowski wave to the press as they arrive for the 17th summit of central European states during a dinner in a presidential palace in Warsaw on May 27, 2011. The US president landed in Poland today on the final leg of his European tour, to meet leaders from ex-communist states whose own reforms could hold lessons for the Arab Spring. AFP PHOTO / JANEK SKARZYNSKI (Photo credit should read JANEK SKARZYNSKI/AFP/Getty Images)