Poland’s ruling party, PiS, is racing to eliminate judicial independence and establish tight control of the country’s judges. One European think tank recently argued that Poland’s government is working to re-create “a Soviet-style justice system … where the control of courts, prosecutors and judges lies with the executive and a single party.”

In attacking the courts, PiS (which, ironically, means “Law and Justice”) has set itself on a collision course with the European Union, which requires its member states to have independent judiciaries. The dispute has been simmering for four years, and with the PiS government’s latest assault on the judiciary, it is finally boiling over.

PiS authorities argue that this is an instance of unwarranted European Union interference in domestic affairs. However, the European Union relies on cooperation between national and European courts, and E.U. membership requires respect for the rule of law, including judicial independence. As Koen Lenaerts, president of the European Court of Justice (the European Union’s highest court), put it earlier this month in a debate at Warsaw University: “You can’t be a member of the European Union if you don’t have independent, impartial courts operating in accordance with fair trial rule, upholding Union law.”

This is the culmination of four years of conflict

The dispute started in January 2016, shortly after PiS came to power, when the new government launched an (unconstitutional) effort to establish political control of the country’s Constitutional Tribunal, triggering a European Commission “rule of law framework” review. This led to four years of strife, in which the PiS government has sought to exert control over judges, and the European Commission has escalated its efforts to defend judicial independence. The Polish government did initially comply with a European Court of Justice (ECJ) ruling that ordered Poland to provisionally suspend its plan to lower the retirement age of sitting Supreme Court judges (in a scheme that would have purged the Supreme Court and allowed PiS to pack it with loyalists), but its retreat was temporary and strategic.

Even while the European Commission had cases pending before the ECJ concerning attacks on judicial independence in Poland, PiS authorities raced ahead to create a new, politically controlled Disciplinary Chamber within the Supreme Court that could sanction judges the government didn’t approve of. The PiS government also seized control of the independent body with the authority to appoint new judges — the National Council of the Judiciary (NCJ) — by abruptly terminating the mandate of existing members and replacing them with PiS loyalists. (As a result, the European Network of Councils for the Judiciary suspended Poland’s new council in 2018 for violating European standards concerning political independence).

Polish judges turned to the ECJ in response, sending more than 20 cases involving questions of judicial independence to the ECJ. Essentially the Polish courts are asking the ECJ to confirm that the assaults on judicial independence being perpetrated by the Polish government are incompatible with E.U. law.

The fight has escalated dramatically

The latest escalation in the rule of law crisis came after a November ECJ ruling on one such case, where the ECJ effectively said that neither the Disciplinary Chamber nor the NCJ offers sufficient guarantees of independence. Poland’s Supreme Court used these findings to rule that the Disciplinary Chamber cannot be considered a real court and that the NCJ lacks the independence to fulfill its mission of appointing judges and safeguarding the independence of courts.

The PiS government responded by rushing the so-called muzzle bill through before Christmas. This new law would enable the government to punish judges for implementing ECJ rulings, or simply for publicly criticizing the government’s attack on judicial independence or questioning the validity of judicial appointments. The bill has been sharply criticized by the OSCE (an international organization that is supposed to safeguard rights in Europe) and other bodies of experts.

Judges play a key role in the European Union

Earlier this month, judges from 20 European countries traveled to Warsaw to join a march in solidarity with their Polish counterparts. The unprecedented march served as a poignant reminder that the European Union is a union based on the rule of law and that it is quite literally held together by a network of judges. Contrary to popular myth, the European Union doesn’t have a large bureaucracy or budget, meaning that it has to rely on courts to enforce its rules when governments or private parties violate them. The European Union mostly lacks the sword and the purse, but it has the robes.

Across the European Union, judges are both judges of their own countries and European judges integrated into the E.U.’s judicial system. This reliance on governance through law and courts is what makes the takeover of a national judiciary so dangerous for the European Union.

The European Union has to take this battle seriously

Poland is in the middle of a constitutional crisis. Over the past two weeks, the ruling party has signaled it is going for broke by initiating more and more disciplinary investigations against judges who apply the rulings of the ECJ and Poland’s (still independent) Supreme Court. On Thursday, the Supreme Court shot back, with a multifaceted ruling saying that the rulings of the politically controlled Disciplinary Chamber are invalid, and that any judicial appointments made by the National Judicial Council are problematic. Now, any rulings made by courts that include judges who were appointed by that council are potentially invalid. The government responded by declaring it would ignore the Supreme Court’s ruling, and the PiS controlled parliament adopted the “blatantly unconstitutional” muzzle bill, establishing a new range of punishments for disobedient judges.

The European Union may start to respond more aggressively to defend Polish judges. Recently, the European Commission took the rare step of asking the ECJ to adopt “interim measures” so as to suspend the functioning of the Disciplinary Chamber. The commission may also bring more actions before the ECJ in coming weeks, possibly targeting the new muzzle bill and the captured Constitutional Tribunal.

Poland’s government would probably pay more attention if the European Union decided to suspend the flow of E.U. funds. Poland is the largest recipient of E.U. funding, and cutting it off from E.U. support would have serious economic consequences. Whatever happens, this fight has enormous consequences for the rule of law in Poland, and in the European Union more generally. The First President of Poland’s Supreme Court said late last year, “the rule of law in Poland is not simply at risk: it is being erased.” If the European Union blinks, other E.U. member state governments with autocratic inclinations are likely to take advantage.

Laurent Pech is a professor of European law, the Jean Monnet chair of European public law, and the head of the law and politics department at Middlesex University London.

R. Daniel Kelemen is a professor of political science and law and the Jean Monnet chair of European Union politics at Rutgers University.