In 2011, a wave of revolution spread through the Middle East as protesters demanded an end to tyranny, corruption and economic decay. From Egypt to Yemen, a generation of young Arabs insisted on a new ethos of common citizenship. Their bravery and idealism stirred observers around the world and led militant jihadists to worry that they had been superseded by a new and peaceful uprising. Five years later, the utopian aspirations of 2011 have darkened. In one country after another, brutal terrorists and dictators have risen to the top as old divides reemerge and deepen.