Hundreds of thousands of people marched through Warsaw on Sunday in a huge display of opposition to the governing party before an October general election, summoning memories of Poland’s rejection of Communist Party rule decades before.
The event, organized by the government’s political rivals, sought to deprive Poland’s deeply conservative Law and Justice party of its claims to the legacy of Solidarity, the trade union movement that led the struggle against a Communist system imposed by Moscow after World War II.
Large protests also took place in Krakow, Szczecin and other big cities controlled by the opposition, which is strong in urban areas but struggles in the countryside.
Law and Justice, which regularly smears its foes as Communists and Russian agents, recently pushed legislation through Parliament to establish a commission to investigate Russian influence and bar individuals from public office for up to 10 years if they were found to have succumbed to it.
The opposition denounced the move as a ploy to tar politicians critical of the governing party with the taint of Russia and disqualify them from running in October. The United States and the European Union voiced concern about the law, widely known as “Lex Tusk” because one of its targets is expected to be Donald Tusk, the main opposition party leader.
In a speech to protesters in Warsaw’s Old Town on Sunday, Mr. Tusk, the leader of Civic Platform, accused Law and Justice of rolling back democracy and turning Poland away from Europe, comparing the coming election to the vote on June 4, 1989 — the country’s first free election since 1945 — which gave a victory to Solidarity and sealed the end of Communist rule.
“The slogan of Solidarity was ‘we will not be divided or destroyed,’” Mr. Tusk said, adding that “the great hope” of democracy’s foes past and present “was our hopelessness, their strength was our powerlessness.”
Referring to the opening line of the Polish national anthem, he added: “It’s over. Today, all of us in Poland, we all see, we all hear ‘Poland has not perished yet,’ we are going to victory.”
Other speakers included Lech Walesa, the Nobel Peace Prize winner and the Solidarity leader who, after the collapse of communism, became Poland’s first freely elected postwar president, only to be denounced later by Law and Justice as an agent of the Communist-era secret police.
Warsaw’s City Hall, which is controlled by political foes of the government, put the turnout at half a million. That was almost certainly an exaggeration but, even accounting for inflated numbers, the march on Sunday appeared to be the biggest antigovernment demonstration since street protests in the 1980s in support of Solidarity.
TVP Info, a state-controlled news channel, reported that only 100,000 people had taken part at most and focused its minimal coverage of the march on obscenities voiced by some protesters, a tactic often used by pro-government news outlets to portray critics of Law and Justice as foul-mouthed infidels opposed to the Roman Catholic Church.
As huge crowds gathered on Sunday afternoon, TVP Info led its news bulletin with a report on the “National Parade of Farmer’s Housewives’ Circles,” a modestly attended event organized by the Ministry of Agriculture.
Law and Justice, in power since 2015, has a big advantage going into this year’s election for Parliament because of its tight control of state television and radio, and its backing by a large battery of nominally independent outlets dependent on state funding. Most opinion polls predict it will win more seats than Civic Platform but will fall short of a majority and could have trouble forming a stable government.