Bangladesh, Oct. 10 -- Immigration, failed integration, political extremism and growing restrictions on free speech are testing whether Western democracies can defend public order without betraying their own principles.

Frances recurring social unrest has exposed a deepening crisis at the heart of European democracy. From Paris and Marseille to Lyon, Lille, Bordeaux, Nantes and Strasbourg, street violence, clashes with police and destruction of public property have raised uncomfortable questions about national identity, immigration, political polarization and the states ability to maintain order.

Yet the real crisis extends beyond broken windows and burning streets. It concerns whether democratic governments can control their borders, i...