“the nationalist wave sweeping across the world cannot return the world to 1939 or 1914. Technology has changed everything by creating a set of global existential threats that no nation can solve on its own. A common enemy is the best catalyst for forging a common identity, and humankind now has at least three such enemies—nuclear war, climate change, and technological disruption. If despite these common threats humans choose to privilege their particular national loyalties above everything else, the results may be far worse than in 1914 and 1939.”