But you have to wonder whether the center can hold permanently, if unemployment remains so extraordinarily high. How must liberal democracy and mixed-economy capitalism look to young people in the south of Europe right now? How stable is a political and ideological settlement that requires the rising generation to go without jobs, homes and children because the European project supposedly depends on it? And for that matter, how well is the Continent’s difficult integration of Muslim immigrants likely to proceed in a world where neither natives nor immigrants can find work?

Already, the Greek electorate has been flirting with empowering a crypto-communist “coalition of the radical left,” even as a straightforwardly fascist party gains in the polls as well. Hungary’s conservative government has tiptoed toward authoritarianism. Spain has seen huge street protests whose organizers aspire to imitate the Arab Spring. And lately, Sweden, outside the euro zone but not immune to its youth unemployment problems, has been coping with unsettling, highly un-Scandinavian riots in immigrant neighborhoods…

Yet there’s a Catch-22 facing Greeks and Spaniards and Italians looking for an alternative to just staying the course. As wrenching as it would be, the option that would do the most to defang extremists of the left and the right would probably be to abandon the euro immediately, with each country regaining control of its own fiscal and monetary policy and seeing what options open up. But at the moment, the only people arguing for that course are … the extremists of the left and the right!