By VANESSA GERA, Associated Press

WARSAW, Poland (AP) — Thousands of Poles chanting "We will defend democracy!" and "Lech Walesa!" rallied Saturday in Warsaw to protest moves by Poland's three-month-old conservative government that they say undermine freedoms and the constitution.

The march was organized by the Committee for the Defense of Democracy, which was formed in November in reaction to moves by the ruling Law and Justice party that have essentially paralyzed the Constitutional Tribunal, preventing it from acting as a check on new government legislation.

"We want a free and open Poland ... a Poland where there is room for everyone," said the head of committee, Mateusz Kijowski.

Thousands gathered in the cold, waving flags and banners and listening to speeches that condemned the government. Police estimated the crowd at 15,000, while Warsaw city hall, which is aligned with the political opposition, said 80,000 people took part.

Many people held up images of Walesa, the former Solidarity leader and ex-president who has faced revived allegations that he was a communist-era secret police informer in the 1970s, before he founded Solidarity, the freedom movement which eventually helped to topple communism.

The protest was held under the slogan, "We the people," — the opening words of the preamble of the U.S. Constitution and also the words that Walesa used when he triumphantly addressed the U.S. Congress in 1989, when communism collapsed across Eastern Europe.

Walesa's supporters accuse the ruling party of trying to destroy his reputation for political gain. Walesa is a longtime foe of Law and Justice leader Jaroslaw Kaczynski.

"We came here to defend a symbol of Polish history against hate," Grzegorz Schetyna, the head of the opposition Civic Platform party, told the crowd. "We are defending Poland against Jaroslaw Kaczynski. We will not allow Poland to be taken over."

Kijowski read out a message from Walesa, who denied that he ever cooperated with the hated communist secret police. Walesa has insisted that the documents that have emerged recently claiming he was a collaborator were forged.

Despite the protest, many other Poles support the ruling party, which swept to power in November by promoting Catholic values and measures to help disadvantaged Poles.