Activists brandished European Union and Polish national flags chanting "shame, shame" and "in defense of the courts" as they descended onto the streets of central Warsaw to rally against the draft bill.
The bill, initially passed on July 14 by the Parliament, emboldens the Law and Justice Party in its ability to replace all Supreme Court judges without governmental oversight. The proposed legislation also envisions that the serving Supreme Court judges would be forced to retire once the new legislation comes into effect.
The demonstrators demanded from President Andrzej Duda to veto a controversial bill that allows deputies and justice Minister to appoint judges without consulting with judicial circles.
"Today we know that a great fight has begun and we know we must be together, we know we must fight against them together", Grzegorz Schetyna, leader of the largest political grouping, the Civic Platform, told the crowd during the rally.
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Demonstrations raged across multiple cities in Poland as the opposition protested against recent legislation approved by the Polish parliament that many see as reducing judicial independence in the Eastern European country.
Poland's TVP television, controlled by the state, said the protests and calls to block Tuesday's debate were "an attempt to organize a coup against a democratically elected power".
Anti-government protests were held in the country's capital, and in other cities.