In December 2010 three of the world's biggest payment providers, Visa, Mastercard and Paypal, cut off funding to WikiLeaks. Ten months later, Julian Assange has announced the whistleblowing site will suspend operations until the blockade is lifted – and warned WikiLeaks does not have the money to continue into 2012 at current levels of funding.

On the surface, it appears as if the bankers' blockade – encouraged by several US senators, including Joe Lieberman – may have come close to accomplishing its goal. WikiLeaks is, for now, silenced – though not before publishing the full cache of 251,000 diplomatic cables, and the files of prisoners at Guantánamo Bay.

The real picture is murkier. As Reuters journalist Mark Hosenball noted at the WikiLeaks press conference, it's not clear exactly which operations WikiLeaks has to suspend: WikiLeaks has not released a single file since the publication of the Guantánamo Bay material – obtained independently by the Guardian and New York Times – in April. The site's primary submissions system has been offline since Daniel Domscheit-Berg and others walked away from WikiLeaks in the summer of 2010. Assange says a replacement will be online by the end of November.

Assange also claims WikiLeaks has over 100,000 documents waiting to be released – but this claim might not bear scrutiny. WikiLeaks has previously been publicly criticised for claiming to hold five million documents when in reality it did not, by John Young of Cryptome.org, in whose name the WikiLeaks website was originally registered.

In reality, WikiLeaks' cupboard presently stands almost bare: Assange has laid the responsibility for the non-appearance of a much-heralded cache of documents relating to Bank of America on sabotage by ex-employees. However, sources close to the site believe the real issue is more mundane: journalists at more than one financial outlet have been given access to review the material, and found nothing of interest.

WikiLeaks' financial claims are similarly questionable. Assange declared the site will need $3.5m to continue operations at their current level. Questions as to who needs $3.5m to publish nothing new in six months aside, this figure is highly dubious.

In 2010, when the Collateral Murder video was published (and a crew flown to Iraq), the Afghan and Iraq war logs were released, and the massive cache of diplomatic cables was unveiled to the world, WikiLeaks spent just €400,000. Given Assange also requested – but was refused – access to WikiLeaks funds towards his bail surety, WikiLeaks' track record on financial claims is also not unblemished.

So given WikiLeaks' status as an unreliable purveyor of financial information, and given its operations might have crashed to a halt with or without financial restrictions, is the banking blockade a mere non-issue? In short, it is not. The banking blockade against WikiLeaks is one of the most sinister developments in recent years, and perhaps the most extreme example in a western democracy of extrajudicial actions aimed at stifling free speech – made all the worse by the public support of numerous people sitting in the US House of Representatives.

Payment companies representing more than 97% of the global market have shut off the funding taps between WikiLeaks and those who would donate to it. Unlike many of the country's leading corporations, WikiLeaks has neither been charged with, nor convicted of, any crime at either state, federal, or international level.

When the Department of Justice mounted a lawsuit against Microsoft in 1998, the idea that payment companies might cut it off due to state disapproval would rightly have been seen as ludicrous and illiberal. Yet when payment companies do exactly this to WikiLeaks, who have never appeared in court opposite the US state, many tacitly accept the action.

Visa, Mastercard and Paypal are none-too-choosy about who they provide payment services for. Want to use your credit card to donate to the Ku Klux Klan? Go right ahead. Prefer to support the English Defence League? Paypal will happily sort you out. Prefer to give cash to Americans for Truth about Homosexuality, who oppose the "radical homosexual agenda"? Feel free to use your Visa, Mastercard or Paypal.

Visa and Mastercard are already inescapable. As the world becomes ever-more digital, and cash continues its journey to obsolescence, they will become still more pervasive. If they are allowed to cut off payment to lawful organisations with whom they disagree, the US's first amendment, the European convention on human rights' article 10, and all other legal free speech protections become irrelevant.

Those who value free expression, whether they like WikiLeaks or loathe it, should hope it wins its current battle.