Thousands of demonstrators marched through the streets of Warsaw and other Polish cities, protesting government moves that have paralyzed the country's constitutional court.
The March 12 demonstrations were the largest since December when the ruling Law and Justice party backed legislative amendments that critics say undermine the Constitutional Tribunal's ability to act as a check on government power.
An estimated 50,000 people rallied in the Polish capital, in front of the Constitutional Tribunal. Protests, were also staged in Poznan and Wroclaw.
Also on March 12, the government again refused to publish a tribunal ruling that struck down the legislative amendments passed in December.
Refusing to publish the ruling prevents it from becoming binding.
The crisis appears to be the most serious since Poland threw off communism in 1989.
With reporting by AP and Reuters