Paul Vallely: The year when the internet came to power

It's already changed the way we live our lives, but the WikiLeaks saga shows it will also change the way governments work

The assault on the royal car carrying Prince Charles and the Duchess of Cornwall last week showed that the old politics is alive and kicking – and daubing paint and smashing windows – as ever. But, threatening though it was, there was something faintly anachronistic about the preposterous cries of "off with their heads". The assault on corporate websites – in retaliation for the global establishment's attempts to shut down WikiLeaks – was, by contrast, singularly modern.

In the old days, leaks came in plain brown envelopes containing a few hastily photocopied pages. But a paradigm shifted last month when the WikiLeaks website began publishing 251,287 secret US military and State Department cables. The largest set of confidential documents ever leaked into the public domain, it did more than embarrass on a bigger scale: it threatened the basis of international diplomacy, which relies on the possibility of frank private exchanges of views, and threatened to compromise the security of nations.

At the heart of this changed game is the internet. For a decade or more, the worldwide web has been creating new ways of doing politics. It began in 1999 with the posting on the internet of a 151-page draft of the Multinational Agreement on Investment. That scuppered what was to have been the most far-reaching international agreement of the 20th century – to remove all regulations on the global movement of money – which Western civil servants were negotiating behind the backs of most politicians. The web passed another milestone in 2006 when, in the US, Congressional candidates with support from the "netroots" – the grass roots on the internet – were found to do better than candidates who lacked such support. In 2008, Barack Obama became the first US president to use the internet to raise large amounts of cash and muster an army of volunteers.

The internet has not only revolutionised politics. It has also changed the way we get our news. Experts blog, offering a critical counterpoint to the traditional media. Ordinary citizens find a platform for views excluded from the mainstream political agenda. Politics has become more participatory. And recent days have shown that protesters do not need to stand on a picket line any more; they can use technology to fight back.

But fight what? Defenders of WikiLeaks say that US government attempts to remove its domain name system and close down its income sources it are assaults on freedom of speech. A group of "hacktivists" worldwide have offered their services in cyber-assaults on companies that have done Washington's bidding.

Most of them are just internet geeks instinctively defending their obsessions. But the WikiLeaks founder, Julian Assange, has a broader agenda. He sees power in information and regards himself as something of a revolutionary. In an essay he wrote in 2006, "State and Terrorist Conspiracies", he quotes Theodore Roosevelt to the effect that "behind the ostensible government sits enthroned an invisible government owing no allegiance and acknowledging no responsibility to the people". Assange goes on: "The more secretive or unjust an organization is, the more leaks induce fear and paranoia in its leadership and planning coterie."

More recently, he told Time magazine that his aim is to push the US towards even greater secrecy, implying that this would bring the current US system closer to collapse. "They have one of two choices. One is to reform in such a way that they can be proud of their endeavours, and proud to display them to the public .... The other is to lock-down internally and cease to be as efficient as they were. To me, that is a very good outcome, because organisations can either be efficient, open and honest, or they can be closed, conspiratorial and inefficient." He also advocated the use of misinformation.

It is not hard to see why this has spooked Washington. US intelligence analysis of the 9/11 attacks showed that a key problem in American unpreparedness was the tendency of different departments and agencies to compartmentalise information. The US government's left hand did not know what the right was doing. For the past nine years, Washington has brought in a series of reforms to share intelligence across government. This allowed a single US intelligence analyst in Iraq, Bradley Manning, allegedly to leak a quarter of a million documents to WikiLeaks. Washington experts fear a recompartmentalisation of intelligence – of the precise kind Assange has outlined – will compromise their ability to piece together information and head off terror plots against the US.

The challenge for us is to separate the good that WikiLeaks has done from its potential for harm. WikiLeaks has performed an important public service in exposing government-backed torture in the "war on terror". It has revealed a casual indifference among Western authorities to the death of innocent civilians in Iraq and Afghanistan. It has shown that Britain allowed the US to keep cluster bombs on its soil in defiance of our treaty obligations. It has disclosed that the US State Department pressured the German authorities to turn a blind eye to the CIA's kidnapping of a German citizen.

But it has also revealed banal tittle-tattle. Colonel Gaddafi loves flamenco dancing. King Abdullah of Saudi Arabia fancies implanting those freed from Guantanamo with tracking chips such as he uses on his horses and falcons. US diplomats say Russia's President Medvedev "plays Robin to Putin's Batman". Such disclosures are not worth the damage they do to world leaders' confidence in the privacy of the conversations they have with foreign diplomats.

The global hackers Anonymous who seek revenge on firms that have abandoned WikiLeaks say their ultimate goal is a "utopian society" which protects "the freedom to share information freely without any censorship". This, like much of what Assange has said, is the rhetoric of student politics. In the real world, lists of spies, secure locations, clandestine operations, vulnerable pipelines and sensitive communications systems must remain secret. It is not ideal, but the world is not an ideal place.

The danger now is that a false polarisation will lead to the defence of useful and legitimate internet freedoms being hijacked by an anti-American, anti-imperialist and anti-globalisation protest. Cyber-attacks, like all terrorism, are far easier to launch than to defend against. The risk is that Western governments will react with a draconian clampdown on the internet, such as the one imposed by China, where sites are blocked, content is filtered and censorship is routine. A requirement that governments have the code for all encryptions, for example, would make the internet a much less attractive place for social or business exchanges.

WikiLeaks ought to be a responsible part of our system of democratic checks and balances. If it becomes the rallying point for oppositionists with a contrary confrontational mindset, we will all be the losers.