Answering questions on the cabinet meeting in the Bundestag on Wednesday, Germany's Interior Minister Thomas de Maiziere said that while the plan wouldn't put a complete stop to travels by German islamists, it would certainly lower the number of departures by making it more difficult to leave the country.

"In the situation we're in right now, effective measures that reduce the problem and not completely solve it are still sorely needed," de Maiziere emphasized.

Without a regular ID, extremists cannot leave the country to fight alongside “Islamic State” (IS) militants in Syria or Iraq. When they return, trained in war and terrorism, these fighters pose a great potential threat to Germany.

The measure comes exactly one week after the attack on French satirical magazine "Charlie Hebdo" by Islamist extremists, who killed 12 people last Wednesday (07.01.2015) and whose accomplice shot one police woman and four hostages in a Jewish supermarket in Paris.

Stopping radical Islamists from leaving Germany, however, is not a new discussion. Merkel's government has to adopt stricter measures in order to comply with the UN "Foreign Fighters" resolution that the Security Council passed in September 2014. All UN member states must make sure that their legal systems provide for the prosecution of travel for terrorism or related training. Since this resolution was passed, the German government has been looking into how existing laws could be modified or expanded.

German ID's special role

The first idea was to mark the IDs of potentially dangerous individuals. This was cast aside in favor of replacing the ID with a substitute document.

"We don't want terrorism to be exported. We don't want men and women to be radicalized here and to travel to Syria and Iraq to come back here ready to fight and to plan attacks," Interior Minister Thomas de Maiziere said when first introducing the concept of the replacement ID in October 2014.

The issue is especially tricky in Germany, because every German citizen gets an ID, or "Personalausweis," when they turn 16 and must present it when signing a cell phone contract, renting an apartment, or opening a bank account. So far, authorities are not allowed to confiscate these IDs.

They can, however, confiscate an extremists' passports under certain conditions. "If there's a danger to public safety or order, taking away the passport is admissible," Frankfurt lawyer Reinhard Marx told DW. This is what already happens with Islamists who are under government observation and who, according to intelligence, are likely to travel to the Mideast to train, or fight ,with terrorist groups, like IS or al-Qaeda.

The problem of free travel

But taking away the passport is not enough to prevent extremists from traveling to a terror camp. The regular "Personalausweis" is sufficient to move freely inside the European Union. It also allows its holder to travel to Turkey - an easy gateway to Iraq and Syria. So even without a passport, German Islamists can manage to join the Jihad and fight alongside IS militants in the Mideast.

So far, around 20 German Islamists managed exactly that. According to nthe ewspapers "Die Welt" and "Hamburger Abendblatt," this is the number of people who joined the civil wars in Syria and Iraq from Germany after their passports were confiscated by the authorities.

And once these fighters have left Germany, the ship has sailed. Prohibiting the re-entry of German citizens is not an option according to German passport law, which states explicitly that "a German must never be denied entry into the area of this law's application."

Potential stigmatization

Politicians from the left side of the political spectrum have voiced their concern about confiscating a person's "Personalausweis," even if a replacement document is issued. The Pirate Party believes that a confiscation based only on suspicion and without a judge's order violates the German Constitution.

Ulla Jelpke from the Left Party calls the measure useless and out of proportion. She is also wary of a potential stigmatization of those who would have to carry a replacement ID. "Those who have to present this document anywhere will immediately be identified as terror suspects," a statement Jelpke issued on her homepage says. But that, of course, is the whole point of the exercise.