Shooting Schengen

WHAT happens at Europe’s borders often telegraphs momentous change. The Soviet blockade of Berlin in 1948 foreshadowed the cold war. The scrapping of a Hungarian fence on the frontier with Austria in May 1989 doomed Soviet rule in eastern Europe months before protests toppled its leaders. Now the reimposition of some border controls by Germany and Austria, to stanch the flow of refugees and migrants, is the harbinger of something dramatic: the erosion and possible demise of the Schengen free-travel area, one of the European Union’s most striking achievements.