AT THE head of a march of thousands in Warsaw on June 4th, Mateusz Kijowski cut a striking figure. The red jeans, ponytail and earrings of the leader of a new Polish mass movement contrasted with the sober suits of the two former presidents who flanked him. Since December, when he founded it, the Committee for the Defence of Democracy (KOD) has turned the formerly obscure 47-year-old IT specialist into one of the most powerful figures in Polish politics. KOD is now in the vanguard of resistance to Poland’s ruling Law and Justice party (PiS), filling a void left by a weak and divided political opposition.

KOD has brought large numbers of Poles onto the streets in nationwide demonstrations; exact figures are fiercely disputed. It has drawn international attention, piled pressure on the government and made Mr Kijowski reviled by PiS supporters. And it has become a conduit for anger at abuse of the rule of law. Since taking power last year, PiS has tried to reorganise Poland’s constitutional court, seized direct control of the state broadcasting channels and the security services, and purged the bosses of state-owned companies. The European Union is reviewing whether its moves violate EU statutes. “We want to have a government that respects the law,” says Mr Kijowski. “We are not fighting against the result of the election, we are fighting against a government that breaks the constitution.”

KOD was born when Mr Kijowski shared an article on Facebook by Krzysztof Lozinski, a journalist, calling for a new political movement to fight the government. The enormous response prompted him to form a group, never dreaming that it would move offline and grow into a mass movement.

“I thought we might get 50 to 100 people when we started,” he says. KOD now has around 230,000 Facebook followers, and the number continues to rise. A survey by TNS, a pollster, found that 1.5m Poles, about 5% of the population, have taken part in KOD events, and that 40% approve of its actions. Before founding KOD, Mr Kijowski says, he had attended only two political-party meetings. As a blogger and activist he had focused on non-partisan issues such as fathers’ rights and combating rape.

KOD’s success has made Mr Kijowski a target. When it emerged that he had fallen behind on alimony payments to his first wife, critics argued he was unfit to take the moral high ground. Some government sympathisers claim KOD must have received support and funding from unnamed outside sources in order to grow so fast. (They have, however, provided no evidence.) Other criticism has come from his own side. Earlier this year a senior member of KOD quit, saying Mr Kijowski ran it autocratically, at odds with its stated ideals, and had treated her “like a slave”.

The attacks have made life difficult at times, Mr Kijowski concedes. Yet so far he has managed to defy those who thought KOD would run out of steam. Many Poles are genuinely infuriated by the government’s actions. And the organisation’s name recalls an earlier era when the people defied their rulers: KOR was the Polish acronym for the Workers’ Defence Committee, Poland’s first big anti-communist group, established in 1976.

But Mr Kijowski has also played a shrewd political game. He has helped broker a loose coalition between opposition parties which has put its weight behind KOD. The renunciation of plans to turn KOD into a party has helped to defray suspicions that its founder aspires to power. Its goals, says Mr Kijowski, lie beyond its dispute with the government: “Our job is to create and support civic society, and this is a job that will never finish.”