A ruling by Belgium’s highest court last week can have far-reaching consequences that can end the practice of enlisting the Kurdistan Workers Party (PKK), an armed group which has been fighting inside Turkey since 1984, as a terrorist organisation in Europe.

The court approved a previous decision made by a lower court in March, which said the PKK could not be considered a terrorist organisation.

While Kurdish activists celebrated the Belgian court’s ruling, both Belgian and Turkish government officials firmly rejected it.

“The decision of the Court of Cassation is the expression of the judicial power, which is strictly independent, and should be understood as such by all actors,” said the Belgian Minister of Foreign Affairs and Defence, Philippe Goffin. “Belgium will therefore continue to defend the placement of the PKK on the European list of persons, groups and entities that are involved in terrorist acts,” he said.

“This ruling of the Belgian judiciary means clear support to the PKK, a listed terrorist organisation by the EU, which is responsible for the death of over 40,000 Turkish citizens including civilians, children and even babies,” the Turkish Foreign Ministry said in a written statement.

The judge’s 51-page verdict mainly explores the answer to the question whether the fight between the PKK and the Turkish state can be defined as a “non-international armed conflict.”

The intensity and duration of a conflict and the organisational complexity and hierarchy of a non-state party are the two most important criteria in defining a group as a party in a non-international armed conflict, said Jan Fermon, one of the lawyers of the defendant.

“For us as lawyers, it was a mental conversion to deviate from the usual line of defence in such cases, which is to plea that the defendants are not terrorists but advocate for a peaceful solution to the conflict,” Fermon said. “Suddenly we found ourselves explaining to the judges that of course (the armed wing of the PKK) the HPG had the capacity to shoot down soldiers, that of course the HPG possessed heavy weapons and of course were able to attack army posts.”

Being unprepared for the defence’s strategy, the prosecutor unintentionally helped the defendant’s case with his arguments. For example, the prosecutor said that the PKK recruited fighters and had communication lines to inform units in the field about movements of Turkish troops and fighter jets.

The judge, in turn, used this information to strengthen the assertion that the PKK is a well-organised non-state party.

International law stipulates that, in a non-international armed conflict, acts carried out by a non-state actor cannot be prosecuted under criminal law, including anti-terrorism legislation.

This principle is connected to the laws of war which determine actions allowed and prohibited on the battlefield.

For example, attacks on military targets are allowed, and in such attacks civilian deaths are permissible as collateral damage, but civilians can never be targeted.

“To encourage the parties in the conflict to respect these rules, it is important that the acts that are allowed in a war can’t be criminally prosecuted. If they could be, the parties would have no incentive to commit to the rules of war,’’ Fermon said.

The defendant’s team of lawyers will now seek cooperation with other lawyers across Europe to see if the same argument can be used in current and future cases against alleged PKK members.

Inside the EU, Belgium is the only country that has rooted the principle in its national legislation. Therefore, in other countries, the defence will have to be based on European and international agreements on combatting terrorism, all of which refer to the principle in the preambles.

Several rulings by the International Criminal Court in The Hague which refers to this principle also strengthens the defence’s case, Fermon said.

The lawyers’ and Kurdish activists’ aim is to put pressure on European politicians to persuade Turkey to return to the negotiating table with the PKK by getting similar rulings in other European countries,

After all, if the PKK is a terrorist organisation, it has to be eradicated. But if the Kurdish issue is a non-international armed conflict, then it has to be resolved.

This one ruling doesn’t do the trick yet, as is clear from the Belgian minister’s reaction, but the lawyers have another card up their sleeve.

The European Court of Justice in Luxembourg ruled in 2018 that the PKK was illegitimately listed as a terrorist organisation between 2014 and 2017 as the European Council had not provided sufficient justification for the decision. At the time, the Council immediately enlisted the PKK again, based on the exact same grounds as the ones that the judge had just wiped off the table.

The Council appealed the 2018 ruling, and ever since the PKK itself has been legally challenging the new EU enlistments which are renewed every six months.

Fermon said the PKK’s lawyers would for sure use the Belgian court’s ruling in their pleas.

“I don’t think it is inconceivable that the European Court will remove the PKK from the list, claiming that the justification is still not sufficient,’’ Fermon said.

It is for now unclear when the court in Luxemburg will announce its rulings on both cases. Its decisions will indicate whether the Belgian court’s decision will have consequences wider than Belgian and European politicians are willing to admit.