Tens of thousands of Poles took part in demonstrations last weekend to protest against the ruling Law and Justice party and what they view as its smear campaign against former President Lech Walesa.

Law and Justice has been accused of waging a “conservative revolution” in Poland by tightening control over key public institutions. Walesa, who won the Nobel Peace Prize after he led the Solidarity union movement that defeated Poland’s communist regime in 1989, is an arch-nemesis of Law and Justice leader Jarosław Kaczynski.

The former electrician from Gdansk faces renewed allegations that he cooperated with the communist secret police in the 1970s before he co-founded Solidarity. The widow of Poland’s last communist chief of secret services, General Czeslaw Kiszczak, offered to sell documents that she claimed prove Walesa was an informer. Because the sale of state documents is illegal, state prosecutors confiscated the files from the ex-strongman’s apartment. Soon after, Poland’s Institute of National Remembrance made the documents public without verifying their authenticity.

The Walesa files have further polarized the country’s two political camps, which have long been divided over how to interpret Poland’s post-1989 history. The two sides emerged from the split between Solidarity activists-turned-politicians after the communist regime fell, which soon spread throughout Polish society. One side insists Warsaw’s transition from socialism to democracy was largely a success. The other maintains that the transition benefitted only a few, and that former communists continue to have a great deal of influence and control over the country.

The protesters accused the Law and Justice party of exploiting the Walesa files to install new national heroes that fit its historical narrative.

“The way they are slandering the man — they didn’t spit on the any of the communists like that,” said 64-year-old Marek Gancarz, one of up to 80,000 people who took part in the Warsaw demonstration on Saturday. The next day, some 15,000 people demonstrated outside the gates of the Gdańsk shipyards, where Solidarity’s antigovernment strikes began. Walesa’s wife, Danuta, who accepted her husband’s Nobel Prize in 1983, told protesters, “I can guarantee he never hurt anyone.”

Kaczynski was a member of Walesa’s presidential administration but was soon ousted for his increasingly radical views. Since then, he has often tried to discredit Walesa’s role in ending communism in Poland — even leading a crowd that burnt the former president in effigy outside the presidential residence in 1994.

Protesters last weekend accused Kaczynski of attempting to rewrite Polish history. In response, the party leader told the Financial Times that his actions are a “reformation, not a revolution.” But critics say he is trampling on Poland’s hard-earned democracy.

“The chairman [Kaczynski] thinks he can do whatever he wants,” said Maria, 53, who stood waving a flag of the European Union. Like many opponents of the government, she insists Kaczynski, who holds no official government office, is the real power. He is the one, they say, who is calling the shots behind President Andrzej Duda and Prime Minister Beata Szydlo.

Opposition leaders united for the antigovernment demonstrations, which were organized by the Committee for Defense of Democracy (KOD), a civic movement founded in November as a response to Poland’s continuing constitutional crisis. Since then, the group has been organizing street protests against controversial changes to the high court and public media.

Warsaw faced increased pressure this week to undo a law that has effectively paralyzed the high court. A leaked draft opinion by the Council of Europe’s Venice Commission says the law undermines the council’s principles. But Warsaw officials have dismissed the report. Szydlo described it as “not binding.” Polish Foreign Minister Witold Waszczykowski, who had invited the council delegation to Warsaw, said the commission was “entering a dangerous path of political dispute with Poland.”

Law and Justice politicians are just as dismissive of KOD’s street protests as of international criticism. Andrzej Zybertowicz, an advisor to Duda, suggested the antigovernment demonstrations could be part of a Kremlin attempt to destabilize Poland; he called Walesa “an informant and a snitch.” Jacek Zalek, a Law and Justice member of parliament, said the protesters were “not the Polish nation.” He accused demonstrators of “having a shady history with the SB (Poland’s communist secret police).

The split in Poland seems increasingly generational. Few young people are taking part in the KOD protests. Many demonstrators are between 50 and 70 years old and were adults at the twilight of the communist era. Younger Poles, meanwhile, are increasingly focused on Poland’s low wages and hope that Law and Justice’s ambitious social policies will help narrow the gap between the country’s living standards and those in Western Europe.

The end of Polish communism 30 years ago is distant history to Poles who came of age in a free Poland. They often sympathize with the nationalistic version of the country’s history promoted by the ruling party.

Older Poles who witnessed the beginnings of Polish democracy are more skeptical. “Even if Walesa’s hands are not completely clean,” said one protester, “he did what nobody else had the guts to do, and history will remember him.”