In 2011, a 21-year-old Kosovo Serb shot dead two US soldiers at Frankfurt Airport, and seriously injured two other people. It was the only Islamist-motivated attack in Germany in the past ten years.

So when Interior Minister Thomas de Maizière honored the Joint Counter-Terrorism Center (GTAZ) on Tuesday (28.10.2014), ten years after it was formed, he portrayed the institution as a success.

But incidents like the airport shooting also show how little power large institutions have, argues Ulla Jelpke, domestic policy spokeswoman for the Left party. Although they collect a lot of data, they have few ways to interpret it. Mostly, lone assailants make a decision to attack on the spot, says Jelpke.

Jelpke also points out that the GTAZ could not prevent thousands of soccer hooligans and far-right radicals clash with the police in Cologne on Sunday, leaving 40 people injured. Security authorities initially only expected up to 1,500 protesters to participate in the authorized "Hooligans against Salafists" demonstration. No one expected a crowd of almost 5,000 violent people.

"I can't say that the GTAZ was particularly successful, where were their assessments?" the Left politician says. And she is not the only critical voice in a current debate on police information.

Behind thick walls

When he set up the GTAZ, Social Democrat Interior Minister Otto Schily hoped for a better, faster exchange of information. The GTAZ wasn't designed to be a new mega-agency, but a centralized network that allowed German security agencies to exchange information.

Police officers and intelligence officials, both federal and state level, sit side by side in a new building in Berlin's Treptow district. They meet for daily briefings and are supposed to cooperate on measures to prevent terrorist crimes, in particular concerning Islamist or far-right extremism.

Before the GTAZ era, individual agencies would often work at cross-purposes. It is up to the 16 federal states to maintain the police forces, and every state has its own domestic intelligence service. Meanwhile, the federal intelligence and military counterintelligence agencies operate at a national level.

"[The GTAZ] has stood the test," concludes Stephan Mayer, a conservative MP responsible for domestic security issues. "The members of the individual agencies have gotten to know each other better, they trust each other."

Centralization has its limits

"For the exchange of information, foreign intelligence services prefer a central contact point instead of intransparent structures and a tangle of authorities," says terrorism expert Rolf Tophoven, who also thinks the GTAZ has proven its value.

The arrest of the so-called "Sauerland group," which had planned a series of bomb attacks in Germany, is the most prominent example of the prevention of terrorist attack. US investigators gave the decisive tip, Tophoven says, and German security authorities did a good job translating that into action.

But what many security experts like about the GTAZ is a matter of concern for many politicians, particularly the opposition Left party. "Lawmakers have no chance of monitoring the work of the GTAZ, and the GTAZ isn't in accordance with the German constitution," Jelpke says.

Germany's constitution provides for a strict division of the police and the intelligence services - as a lesson learned from the country's Nazi past under Adolf Hitler. If police and intelligence agencies exchange information on a regular basis, they're breaching this dissociation act, Munich-based expert Matthias Becker warns.

Stephan Mayer says this act is still being complied with, and no agency was given additional powers. As before, only the police are allowed to make arrests. Facilitating the agencies' exchange of information simply makes sense, says Mayer. Chancellor Angela Merkel's government agrees.

What remains is the realization that in the future, the GTAZ can only be as efficient as the individual agencies that use it. If they do "a sloppy job," there's no point in the GTAZ, says Jelpke - pointing once again to Sunday's riots. But Mayer argues that the GTAZ is just one measure in the fight against terrorism and extremism: "You can't expect too much." Inquiries in the run-up to terrorist attacks are what matters, says Mayer - not speculation about potential riots during demos.