The European Union’s executive may trigger a process on Wednesday to begin to strip Poland of its voting rights in the bloc, officials say, as months of tensions between Brussels and Warsaw come to a head.

In what would be an unprecedented move, the European Commission could invoke Article 7 of the European Union’s founding Lisbon Treaty to punish Warsaw for breaking its rules on human rights and democratic values.

“Unless the Polish government postpones these court reforms, we will have no choice but to trigger Article 7,” said a senior EU official before a Commission meeting on Wednesday, where Poland’s reforms are on the agenda, as reported by Reuters.

Poland’s new prime minister Mateusz Morawiecki said in Brussels last week that “the decision has already been made”. The Commission’s deputy head Frans Timmermans warned in July that Poland was “perilously close” to facing sanctions.

Such a punishment could still be blocked. Hungary, Poland’s closest ally in the EU, is likely to argue strongly against it. But the mere threat of it underlines the sharp deterioration in ties between Warsaw and Brussels since the socially conservative Law and Justice (PiS) won power in late 2015.

The Commission says Poland’s judicial reforms limit judges’ independence. Polish President Andrzej Duda has until Jan. 5 to sign them into law. If all EU governments agree, Poland could have its voting rights in the EU suspended, and may also see cuts in billions of euros of EU aid.

The PiS government rejects accusations of undemocratic behavior and says its reforms are needed because courts are slow, inefficient and steeped in a communist era-mentality. Following a non-binding European Parliament vote last month calling for Article 7 to be invoked, the Commission appears to have little leeway to grant Warsaw more time to amend its legislation.

The reforms would give the PiS-controlled parliament de facto control over the selection of judges and end the terms of some Supreme Court judges early. The Council of Europe, the continent’s human rights watchdog, has compared such measures to those of the Soviet system.

The Commission fears letting Poland off the hook could weaken its hand, especially in the ex-communist east, and risk damaging the EU’s single market and cross-border legal cooperation.