The supranational risks and opportunities of the interdependent twenty-first century urge us toward supranational cooperation and a shared identity as global citizens. And the good news is that such an identity is on the rise: half the people surveyed in a new poll of eighteen countries now identify more as global citizens than as citizens of their own country. The trend augurs positively for the future, but masks an underlying divergence: the sense of global citizenship is rising in developing countries, but falling in developed ones. In Germany, for instance, identification with global citizenship has been on a steep decline since the 2009 financial crisis and is now at its lowest in fifteen years, with particularly weak support for immigration and accepting refugees from conflict-prone regions. Will the rising cosmopolitanism of the Global South spell a more democratic and cooperative global future, the foundation for a Great Transition? Or will xenophobia and economic turmoil in developed countries usher in a Fortress World? “The Earth Flag is my symbol of the task before us all,” said Margaret Mead, a prescient edict for us all.