The dream of a United States of Europe is unraveling in the wake of several crises now afflicting the continent. The single Euro currency threatens to break apart amid bitter arguments between rich northern creditors and poor southern debtors. Russia is back as an aggressive power, annexing Crimea, supporting rebels in eastern Ukraine, and waging media and cyber warfare against the West. Marine Le Pen's National Front won a record 34 percent of the French presidential vote despite the election of Emmanuel Macron. Europe struggles to cope with nearly two million refugees who fled conflicts...