In the past seven days, German civilians have come under attack from four men of Middle Eastern or Asian origin. Three have been linked to Isil. The latest incident saw a Syrian blow himself up outside a Bavarian festival after pledging allegiance to Isil.

Joachim Herrmann, Bavaria’s interior minister, has suggested that such attacks raise questions about an immigration policy that has seen more than one million migrants enter Germany largely unchecked over the past year, many from Syria, Iraq and Afghanistan. Raising such questions may appear logical and sensible, but Germany’s debate about migration issues does not always follow logic or common sense. Thomas de Maizière, the federal immigration minister, attempted to argue that the open door offered to migrants by his boss, Angela Merkel, is not relevant to the recent attacks.