Poland's attack on the EU court has nothing to do with questioning its EU membership, the head of the country's ruling party has said.

"This has nothing to do with any 'Polexits' or anti-Europeanism," Jaroslaw Kaczynski, the head of the Polish ruling party, Law and Justice (PiS), told Polsat News, a Polish broadcaster, on Wednesday (17 October).

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"This idea [of a Polish exit from the EU] was promulgated for propaganda reasons [by the opposition]. It doesn't hurt PiS, but it harms Poland," he added.

"We've always been pro-European, in the sense of supporting Polish EU membership, and we haven't changed our minds," he said.

Kaczynski spoke after PiS prosecutor general Zbigniew Ziobro questioned the validity of the EU treaty.

He did it by asking the Polish Constitutional Tribunal, earlier this month, whether Polish judges had the right to ask the EU high court in Luxembourg for preliminary rulings on interpretation of EU law.

The move comes amid a judicial dispute between Poland and the European Commission, which said a PiS purge of Polish Supreme Court judges amounted to political meddling.

The commission referred the case to the EU top court, but Ziobro's query, which questions the primacy of EU law in Polish affairs, could be a pretext to ignore the looming EU verdict on the Supreme Court affair.

Big questions

It could also pose bigger questions for Poland's future EU membership, judicial experts have warned.

"If the Polish Constitutional Tribunal questioned the validity of the EU Treaty it would amount to an exit from the EU," Jerzy Stepien, the former president of the Polish Constitutional Tribunal, told the onet.pl news agency.

"It's playing with fire because without EU court referrals there is no common legal order in the EU which constitutes a union ... without this you just have 28 separate jurisdictions, there would be no EU," he said.

Krystian Markiewicz, the head of Polish judicial association Iustitia, noted that Ziobro's query could be used to "bully" Polish judges in future.

If the Polish Constitutional Tribunal rejected EU referrals "it would be a pretext [for PiS] to hunt down those judges who dared to refer questions to the EU Court of Justice," he said.

German precedent

Kaczynski, Poland's de facto leader, defended Ziobro's move by saying that the German Federal Constitutional Tribunal had in the past looked at "the same kinds of issues".

But he refused to back down in the EU judicial dispute, saying the Supreme Court purge would go ahead.

"Polish citizens will shortly have decent courts" when "better people" filled the judicial posts, Kaczynski said.

The EU dispute could lead to sanctions against Poland or to indirect punishment, such as lower EU funds for Polish regions in the next EU budget.

But the PiS chief batted away the threat, saying: "The [EU] money will be there and it will be better used than it was in the past."

Ziobro himself also downplayed the idea that his constitutional query had big implications.

"Poland feels very good in the EU," he said at a conference in Poland on Wednesday.

The talk of Polexit was "manipulation by a special caste", he said, referring to anti-PiS Polish judges.

Polish opinion

"These manipulations are the work of a sect, which is misleading public opinion," he said.

If the German federal tribunal examined matters of EU law back in 2009, then "I see no reason why we [Polish people] should feel complexed about it and shouldn't be able to ask the same questions of the Polish Constitutional Tribunal," Ziobro said.

The debate on "Polexit" comes ahead of Polish local elections on 21 October and general elections next year.

PiS is polling in first place with about 40 percent of the vote, but alarm bells on EU relations could harm support, with 70 percent of Polish people telling a recent EU survey that they viewed membership as a "good thing".