BRUSSELS (AP) — The European Union on Wednesday escalated its standoff with Poland's new government, deciding to open a case over new laws affecting the country's constitutional court and media that have been criticized as running counter to the bloc's fundamental principle of the rule of law.

EU Commissioner Frans Timmermans said his executive will carry out a preliminary assessment — the first step in a drawn-out procedure that could ultimately lead to suspending Polish voting rights in the 28-nation bloc.

Timmermans said he wanted specific explanations about changes in procedure at the constitutional tribunal "which could potentially limit the leeway for action in the court and increase political influence" on it.

The debate is seen in Poland as undue meddling in national affairs and in Brussels as a potential danger that democratic standards in the bloc's members may be slipping.

"Poland is an extremely important member state," Timmermans said.

In Warsaw, Prime Minister Beata Szydlo defended her government's moves.

"Poland has the right to take sovereign decisions concerning the course of home affairs or how the media need to be organized. This is a sovereign decision of any state, including Poland," Szydlo said.

The Polish government said Timmermans has been invited to Warsaw for talks on the Polish laws.

In December, Poland's ruling Law and Justice party, which has a parliamentary majority, took steps to gain influence in the constitutional tribunal, which is supposed to be an independent arbiter with the power to block the government's legislation. It is currently dominated by judges linked to the opposition.

In addition, Poland's president signed a law last week that heads toward giving the government full control of state radio and television, a move that critics see as undermining free speech.

Even before Wednesday's announcement, the Polish government criticized the EU for wading into Polish affairs.

"In the future, please have more restraint in instructing and reprimanding the parliament and the government of a sovereign, democratic country," Polish Justice Minister Zbigniew Ziobro wrote to Timmermans.

On Wednesday, Timmermans said "regardless of the tone of the letter, it is clear they want to have a discussion with us."

The EU has had similar issues with Hungary, whose Prime Minister Viktor Orban, a recalcitrant member on many EU issues, has stressed his support for Poland.

The EU has never had to move toward suspending the voting rights of a member state.

The threat of such a measure and the long procedure "worked in the case of Orban's overreach in Hungary," said Guy Verhofstadt, the leader of the ALDE liberal group in the EU Parliament, who urged Timmermans to "do the same before the situation in Warsaw gets out of control."

Scislowska reported from Warsaw

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