Moscow Ilya V Ponomarev stood on stage before a churning crowd of more than 50,000 anti-government protesters in downtown Moscow, his blue eyes narrowed against a rainy wind, his right hand chopping and punching the air.

“Don’t we know the nature of the authorities we live under? Don’t we know exactly what Putin is?" he shouted at the rally this month. “We must act!”

The wind whipped at the white ribbon pinned to his lapel. “We need to go on the offensive. We need to stop talking and instead to truly become the power, because we are the power here,” he proclaimed, breaking into a staccato declaration of ‘We! Here! Are the Power!’

The crowd chanted along. “We - here - are the power!”

Ponomarev, 36, is not just a disgruntled rabble-rouser. He is a member of the State Duma, the lower house of Parliament, and he is attempting something rarely seen in modern Russian politics: He is trying to upend the establishment, while also serving in it, which has left him viewed with suspicion on all sides.

A scientist by training and an information technology entrepreneur by profession, Ponomarev is one of just two federal elected officials helping to lead the protests against the government of President Vladimir V Putin. (The other is his friend and fellow lawmaker Dmitry G Gudkov, 32.)

On the street, where he is a constant presence at demonstrations, Ponomarev can seem overly genteel. He is not as radical as the leftist Sergei Udaltsov, nor as eloquently biting as the anti-corruption activist Alexei Navalny.

Instead, he projects himself as a pragmatic, if not particularly electrifying, proponent of change. Often, he serves as an intermediary between protesters and the riot police, a role that is easier for him because as a Duma member he enjoys immunity from arrest and prosecution.

“Some people even call me the lawyer of the street protests,” he said.

But in Parliament, where he and Gudkov are members of Just Russia, a minority faction, he is regarded as young troublemaker, intent on adding a dash of street rebellion to a body that for more than a dozen years has served as little more than a rubber stamp for Putin's policies.

This month, Gudkov, Ponomarev and others staged the first filibuster - or “Italian strike” as the tactic is called in Russian - since Putin rose to power. While it ultimately failed to stop passage of a law that would impose steep fines on political protesters, it generated wide publicity and illustrated that the majority United Russia party no longer enjoyed unfettered control.

Most important, Ponomarev said, it was a step to building a viable opposition and fostering genuine debate.

Unlike other protest leaders, Ponomarev and Gudkov have not had their homes searched by investigators. But it is increasingly unclear how long their participation in the protests will be tolerated.

At the rally June 12, Ponomarev opened his speech by joking darkly about the possibility of a crackdown on opposition lawmakers. “Hello, friends, from the Duma members who are free for the time being,” he said.

Being an anti-government crusader on the government payroll is not the only apparent contradiction in Ponomarev's life. He is an avowed communist who made a lot of money as a technology entrepreneur working for major corporations. He is a leader of anti-globalisation protests who owns homes in Boston and Palo Alto, California, and has business ties around the world.

Ponomarev has swerved in and out of business, politics and government.

He was an executive of Yukos, once Russia’s largest oil company, where he helped design computer systems. He was the chief information officer of the Communist Party, and a member of the Central Committee. He helped build the party's website and an electronic vote-counting system that helped prove fraud in legislative elections in 2003.

He has worked for the Moscow mayor’s office, promoting entrepreneurship, and even for the Putin government as leader of a national effort to build high-tech parks. He is married and has two children, and his parents are both well-connected scientists. His mother, Larisa Ponomarev, is a member of the upper chamber of parliament, the Federation Council, where she was the only member to vote against the law imposing steep fines on demonstrators.

It is his ability to manoeuvre in these conflicting worlds - operating as a pragmatist - that Ponomarev insists will prove invaluable to the political opposition in its effort to change the Russian government.

“That is how I try to position myself - as a bridge, because at the end of time we need to negotiate,” Ponomarev said. “Whether there will be peaceful negotiations at a round table or negotiations of unconditional surrender, there has to be somebody who is capable of talking to those guys.”

If Ponomarev gets his wish, the negotiations with “those guys” - meaning Putin and his supporters in the government - will begin soon rather than later. “I think that this regime will not survive another two years; it might not even survive a year,” he said.

Conjuring how and when - not if - Putin will fall is the opposition leadership's favourite pastime. Ponomarev has narrowed the potential chain of events to three.

“Best case,” he said, “Putin would engage in some talks, negotiations, and we can do a peaceful, gradual transition of power. We will be ready to give him all the guarantees.”

“Another scenario,” he continued, “is more violent, not necessarily violent like bloody, but outside the legal framework where he will be forced out of the Kremlin. And that's the most likely scenario. I don't know when it would happen. The movement would grow. There would be more and more people in the streets”.

“Third case,” Ponomarev said, “is the worst scenario actually. There might be a coup within Putin's own establishment, and most likely it would come from the security guys, which would make a car accident, heart attack or some other scenario like that and would nominate somebody from their own circle”.

The main obstacles, he acknowledges, is that the opposition is not ready, and has yet to identify a leader who can win broad support. At the moment, Navalny seems the likeliest choice, but he has resisted calls to create and lead a new political party.

Meanwhile, rivalries are developing, and the conditions for Putin's ouster may never develop beyond the theoretical.

Even some of Ponomarev’s closest friends and allies acknowledge that it will not be easy for him to build trust, given his ties to the establishment.

“Nobody trusts politicians - we have got a huge crisis of credibility,” said Alena Popova, a friend and partner of Ponomarev's in several business and political ventures. "I don't trust him. But I believe in him. I know he's the right man to change something."