No person has snatched, wielded and lost more power in the past 18 months than Julian Assange. The WikiLeaks founder has been responsible for the publication of hundreds of thousands of US government secrets, helped spark revolutions and changed the face of journalism — perhaps forever.

Now, he’s under virtual house arrest and may soon find himself in a Swedish courtroom. He’s also a wanted man by the US government who want him to answer for what he’s released. Meanwhile, his organisation is close to broke.

Along the way he’s tried to revolutionise the way people leak confidential information, using the power of the internet to harvest and distribute massive tranches of sensitive documents.

Assange tells The Power Index WikiLeaks is an organisation intent on freedom of information and helping the public see in full view how their governments operate. “It is our role to make sure that information relevant to that is published,” he says.

And he’s managed to do just that through a series of major newsworthy leaks. Most prominently with the publication of classified documents concerning the conflicts in Iraq and Afghanistan, and then with the disclosure of more than a quarter of a million secret US embassy cables.

It’s the latter, aided by major newspapers worldwide, which has been credited by groups like Amnesty International with having helped spark last year’s Arab Spring protests. In the process it’s made Assange both an iconic and vexed figure: journalist freedom fighter to some, treasonous spy to others.

“We thought that they would cause a lot of discussion and debate around the world, we specifically thought that they would restabilise the Middle East,” says Assange when asked what effect he anticipated Cablegate would have. “They do seem to have contributed towards the revolutions there and perhaps the most significant ongoing thing to come out of them was the radicalisation of internet-educated youth.”

Assange acknowledges WikiLeaks wasn’t alone in what happened in the Middle East. Social networking sites like Twitter, Facebook and YouTube are also said to have played a role in helping to mobilise the protests, as did the coverage of WikiLeaks’ media partners.

But when you consider the allegations of corruption the cables revealed, it’s not too much of a stretch to say the Townsville-born hacker was at the centre of a revolution.

During our phone interview (despite expectations, there was no Skype chat) Assange is measured and calm, pausing for a brief moment of thought before answering each question. We speak to him not long before his current extradition hearing in a UK Supreme Court.

He says everything that’s mentioned in an official communiqué back to Washington is important, no matter how trivial it seems. “If it’s poisonous gossip it is extremely important when it’s sent from Karachi to Washington,” Assange tells The Power Index in his familiar baritone voice. “It is no longer mere gossip, it is an instrument of diplomacy.”

WikiLeaks has provided a new model for how people leak information. In theory, the concept makes it possible for anyone with an internet connection to be able to safely disclose state and corporate secrets without fear of being uncovered. The encryption is supposed to be so good even WikiLeaks doesn’t know its sources.

As Suelette Dreyfus, author of cult classic hacking book Underground (on which Assange collaborated), puts it: “His idea was to use technology to make it safer for whistleblowers … his idea changed the risk profile for revealing wrongdoing.”

It’s all part of Assange’s open governance philosophy, built on his background as a computer hacker breaking into organisations like NASA and the Pentagon as a teenager. It’s a concept prominent academic Robert Manne lauds as one of the “few original ideas in politics”.

And if a measure of influence is having imitators, then Assange scores highly: a string of WikiLeaks copycats have popped up since its inception.

“There’s no doubt that WikiLeaks, and by extension Assange, has been responsible for some of the most important and game changing acts of journalism over the past two or three years,” Chris Warren, secretary of journalists’ union the MEAA, tells The Power Index.

Tall and slender, with his trademark shock of ghost-white hair, the 40-year-old Assange has one of the most recognisable faces in the world. Adding to his mystique is a penchant for dark suits, which gives him the air of an international jewel thief.

*Read the full profile at The Power Index