In the two years prior to the erection of the controversial border installations, Israeli authorities counted 89 attacks, with 305 deaths and 4,942 injuries — a significant number for a country with a population of just over 8 million. The number of casualties only began to fall after the construction of the wall. It’s a success story that has never been viewed as such outside of the embattled country itself.

In Germany, we won’t be able to build walls through our major cities in order to protect ourselves. The enemy we are dealing with doesn’t live on the other side of the desert, it lives in our midst. We are left to rely on the acumen of people who have been trained to detect evil before it is too late.

Unfortunately, we are poorly equipped for the task. Germany’s Office for the Protection of the Constitution, the country’s domestic intelligence agency, is in an extremely poor state — as any official there would confirm. It is only with great effort that domestic intelligence agents are able to track jihadists who have returned home from war zones. Cases where they succeed in neutralizing these fighters before they take up arms and engage in holy war in Pforzheim or Dinslaken, tend to be the result of a chain of lucky circumstances rather than of systematic investigation.