The European Court of Human Rights (ECHR) ruled on May 7 that a Polish company could not get a fair trial because the Polish government illegally appointed a judge to the Constitutional Tribunal that had reviewed the company’s case.

The ECHR’s ruling sends a shock wave deep through the Polish government-orchestrated overhaul of the country’s judiciary. It could open the door to undermine any of the tribunal’s rulings issued by judges whose appointments are deemed illegal.

The ECHR “lawlessly interfered into the competence” of Poland’s authorities, the head of the Constitutional Tribunal, Julia Przylebska, a government loyalist, said, according to the state newswire PAP.

"Is Poland now going to contest if we're bound by the European Convention on Human Rights," a lawyer Sylwia Gregorczyk-Abram said in reaction, gazeta.pl reported.

Poland has long been at loggerheads with the EU over the changes. Brussels eyes them with utmost suspicion as an attempt to bring courts to direct political control of the government via, for example, a system that allows disciplining judges for their rulings.

The ECHR case centred on a complaint by a Polish rolled-out turf producer, which complained that Poland’s hunting laws did not guarantee receiving compensation if game like deer or wild boar damaged the company’s product.

The case had made it through to the Constitutional Tribunal, which ruled in 2017 that the company’s complaint was inadmissible. One of the judges who was on the panel that issued the ruling is Mariusz Muszynski, who the government-controlled Polish parliament, the Sejm, appointed to the tribunal despite his seat having already been filled by the previous parliament.

“The applicant company had been denied its right to a tribunal established by law, owing to the irregularities in the appointment of Judge [Muszynski] specifically,” the ECHR said.

Poland’s ruling Law and Justice (PiS) party began its contested changes to the judiciary by planting loyalists in the Constitutional Tribunal in late 2015. The party ultimately took control of the key court in late 2016.

Poland’s government has recently asked the Constitutional Tribunal to rule if EU laws take precedence over Poland’s domestic regulations, a potentially explosive question to Poland’s membership in the bloc.