What would the Catalan independence movement be without the Spanish justice system? With its bans, subpoenas, arrest orders and convictions, which are often characterized by their utmost severity, it succeeds again and again in driving the Catalan masses into the streets in protest.

For a long time, the protests against the justice system had been conspicuously peaceful. On Sunday, after former Catalonian President Carles Puigdemont was arrested upon entering the German state of Schleswig-Holstein -- based on orders from Madrid and orchestrated from the Spanish capital -- those protests escalated.

Now, the world is watching Germany to see whether the country will extradite Puigdemont. The responsible judicial officials in Germany -- both in Schleswig-Holstein, where he is currently being detained and courts are expected to rule on the extradition, and the national capital in Berlin -- must do everything in their power to defuse the crisis.

Puigdemont's arrest was based on a European Arrest Warrant. Several years back, European Union member states introduced procedures simplifying cross-border extraditions, to be used in areas like combating terrorism. The arrest warrant is based on mutual trust and on all participating countries obeying the rule of law, and having a working and politically independent judiciary.

It isn't just separatist leaders who are expressing doubts about the independence of some Spanish judicial organs. It's clear that many public prosecutors are not independent -- the attorney general, for example, is appointed by the central government in Madrid. The examining magistrate who ordered the first arrests in October had been honored with a medal by the interior minister in Madrid two weeks before, giving the episode an unsavory flavor.

But the judges on the Spanish Supreme Court who now want to place Puigdemont and his comrades on trial are appointed by a council that is in turn elected by the Spanish parliament. Legal scholars as well as Judges for Democracy, an association of Spanish judges and magistrates, are largely united in the view that the council is capable of filling judicial posts at its own discretion. And the judges, for their part, are able to make independent decisions in their everyday work.

There have also been few European Court of Human Rights verdicts against Spain. And in its "Democracy Index," the London-based Economist counts Spain as one of only 19 "full democracies."

There are no known questionable connections between politicians and Spanish Supreme Court Judge Pablo Llarena, who issued the European Arrest Warrant against Puigdemont and others for, among other charges, possible misappropriation of public funds and rebellion. It's possible that the separatist leaders did, in fact, use taxpayer money to organize the banned independence referendum.

A Trial for Misappropriation, But not for Rebellion

But Llarena may be going out on a limb with the charge of "rebellion," which could result in a prison sentence of up to 30 years for Puigdemont. Under Spanish law, the charge requires the actual use of force, but Puigdemont and Co. have never used or even called for violence. Llanera wrote that, after a raid of Catalan government ministries by Spanish forces, the politicians called for protests and hazarded the risks of possible violent acts by agitated crowds. But that's an extremely broad interpretation of the term violence, to say the least.

The German judicial authorities must now decide whether to extradite Puigdemont. And if they decide in favor of extradition, they will also have to be prepared to defend their decision. They are not entitled to review the material substance of the allegations. Where they do have some leeway, though, is on the question of whether the same actions would also be punishable here in Germany. The answer to misappropriation of public funds is a clear "yes."

Far less clear is the main allegation of "rebellion." The section of the German penal code pertaining to "high treason against the federation" is not directly comparable to the idea of "rebellion" in Spanish law. And this is where things get very delicate, because if Germany only extradites Puigdemont based on the charge of misappropriating public funds, then that is all the Spanish judiciary can put him on trial for back in Spain. It cannot put him on trial for the rebellion charge.