Polish Supreme Court Justice chief Małgorzata Gersdorf | Janek Skarzynski/AFP via Getty Images Poland’s Supreme Court slams PiS’s judicial changes The country’s justice ministry has already fired back, saying it would not respect the court’s decision.

Poland’s judiciary crisis deepened on Thursday as the country's Supreme Court fought back against the government’s judicial reforms, ruling against the body that appoints judges and members of a controversial new disciplinary chamber.

The court ruled overwhelmingly that judges appointed by the new body are not judges under either Polish or EU law — although verdicts that such judges may have issued will remain valid if they were made before Thursday.

The country's justice ministry quickly fired back, saying it would not respect the ruling, which it said had been issued "in gross violation of the law."

That sets up Poland's nationalist Law and Justice (PiS) government for a clash with the European Commission, which is increasingly worried about the country's slide into legal chaos thanks to the judicial changes wrought by PiS.

The Supreme Court decision came in response to a top EU court ruling in November, which said the new disciplinary body could undermine judicial independence, but threw the case back to the Polish courts to make a final determination.

The Court of Justice of the EU said Polish courts could test the chamber by checking whether the National Council of the Judiciary (NCJ) — the body that appoints the chamber’s members, as well as all court judges — is under political influence.

A major component of PiS's judicial reforms was to change the way people are selected to join the NCJ, and also replace all of its members with the input of the parliament, which is dominated by the ruling party. The government argues that the changes are needed to root out the remnants of the communist system — which ended in Poland in 1989.

Critics of the reforms argued this process undermined the independence of the judiciary, because it made the NCJ dependent on the executive and legislative branches of government.

The government has made it clear it wants obedient judges.

"We have nominated judges who, in our view, would be ready to cooperate in reforming the judicial system," Justice Minister Zbigniew Ziobro said last week.

The government tried to block lower court inquiries into the validity of the new NCJ, but Thursday's ruling makes it clear that the country's top court has taken a hard line against the chamber.

However, the ruling party has cast the ability of the Supreme Court to rule on the matter into doubt.

Elżbieta Witek, the PiS speaker of the Sejm, the lower chamber of parliament, said on Wednesday that it’s unclear if the Supreme Court is the right institution to make decisions about the judiciary system. Witek referred the case to the Constitutional Tribunal, which is controlled by PiS appointees, saying it was the more appropriate body to regulate any conflicts between the courts and the legislature

The tribunal tried to suspend the Supreme Court's hearing, but Małgorzata Gersdorf, the court's chief justice, rejected the tribunal's reasoning.

The European Commission — which has also launched an Article 7 procedure against Poland over concerns that it is violating the EU's democratic standards — has referred its own case over the disciplinary chamber to the EU court.

Meanwhile, PiS lawmakers in the Sejm on Thursday voted in favor of a bill dubbed the “muzzle law” by critics, which penalizes judges who question the legitimacy of the government’s legal changes — overturning a decision by the upper house senate, which had rejected the bill.

The bill, which was rushed through the Sejm for the first time in December, is a direct response to the EU court ruling, as in practice it means judges could be disciplined for raising doubts about the legality of the NCJ. The law now awaits the signature of President Andrzej Duda, who has already signaled his support.

The bill has been criticized by the European Commission, the Council of Europe and, most recently, by two U.S. Congressional members.