Those of us who have been concerned with the massive assault on civil liberties have warned that all the so-called ‘anti-terror’ measures that are being rammed through for the ostensible purpose of fighting terrorism would be also used against anyone whom the government does not like, and that those who casually dismissed those concerns might one day find themselves in the cross-hairs. Those alleged realists who adopted a worldly-wise air and airily treated due process and constitutional protections as quaint relics of a bygone era that need to be dispensed with in our hard-eyed effort to protect ourselves from terrorism dismissed these arguments as fear-mongering, placing their trust in the supposed goodness of political leaders that they would not abuse the powers they had seized.

The case of David Miranda will, I hope, open their eyes. I was traveling all day yesterday and so came to this story late but feel compelled to write about it because if there is any story that provides an open-and-shut case of how the government can and will abuse its powers, this is it.

For those who missed the story, David Miranda is Glenn Greenwald’s Brazilian partner and they live together in Rio de Janeiro. (You may recall that it was Miranda’s computer that was mysteriously stolen from their home in Rio back in June, just after Greenwald sent him an email from abroad telling him that he was going to be sending him an encrypted file.)

Miranda was in Berlin to meet documentarian Laura Poitras who has been at the center of the Edward Snowden story from the beginning, being the person who first realized that he would be the source of a huge revelation. The trip had been arranged by The Guardian. On his return trip to Rio, Miranda made a transit stop in London during which he was detained under Britain’s Terrorism Act and held for questioning for 8 hours 55 minutes and then allowed to leave, although the police kept his mobile phone, laptop, camera, memory sticks, DVDs and games consoles. Nine hours is the maximum time someone can be held without having to be arrested and charged. During that time, he was refused access to a lawyer, a deep irony for someone with his name.

What was the point of this? Let’s dismiss the idea that he happened to be stopped at random.

Widney Brown, Amnesty International’s senior director of international law and policy, said: “It is utterly improbable that David Michael Miranda, a Brazilian national transiting through London, was detained at random, given the role his partner has played in revealing the truth about the unlawful nature of NSA surveillance.

“David’s detention was unlawful and inexcusable. He was detained under a law that violates any principle of fairness and his detention shows how the law can be abused for petty, vindictive reasons.

“There is simply no basis for believing that David Michael Miranda presents any threat whatsoever to the UK government. The only possible intent behind this detention was to harass him and his partner, Guardian journalist Glenn Greenwald, for his role in analysing the data released by Edward Snowden.”

I think there were two reasons for the UK government’s action. One is that Laura Poitras has been detained and questioned and had her equipment seized so many times whenever she enters the US that she has become highly security savvy and takes extraordinary steps to protect her information from the government. Snowden knew this and was the reason why he picked her as his conduit for the documents. One of the precautions she takes is to send material back to the US via other people. The US government was clearly tracking Miranda’s movements and obviously asked the British government, always pathetically eager to please their US overlords, to grab his stuff in case he was acting as Poitras’s courier.

But that search and confiscation could have been done fairly quickly. The unusually long interrogation was clearly also an attempt to intimidate Greenwald, Poitras, and all the other journalists working on this story by letting them know that their families, friends, and loved ones are being monitored and will also be harassed.

This was an unbelievably stupid move on the part of the UK and the US because the principal figures involved are not the kinds of people who are going to back down in the face of this kind of threat. Greenwald provides a detailed account of what happened and says that this effort at intimidation will only backfire.

This is obviously a rather profound escalation of their attacks on the news-gathering process and journalism. It’s bad enough to prosecute and imprison sources. It’s worse still to imprison journalists who report the truth. But to start detaining the family members and loved ones of journalists is simply despotic. Even the Mafia had ethical rules against targeting the family members of people they felt threatened by. But the UK puppets and their owners in the US national security state obviously are unconstrained by even those minimal scruples.

If the UK and US governments believe that tactics like this are going to deter or intimidate us in any way from continuing to report aggressively on what these documents reveal, they are beyond deluded. If anything, it will have only the opposite effect: to embolden us even further. Beyond that, every time the US and UK governments show their true character to the world – when they prevent the Bolivian President’s plane from flying safely home, when they threaten journalists with prosecution, when they engage in behavior like what they did today – all they do is helpfully underscore why it’s so dangerous to allow them to exercise vast, unchecked spying power in the dark.

This act also exposes the fact that the US and UK are abusing anti-terror laws to go after people who are engaging in perfectly lawful activities. This was clear from the questioning Miranda received.

“They never asked him about a single question at all about terrorism or anything relating to a terrorist organisation,” [Greenwald] told the BBC World Service’s Newsday programme.

“They spent the entire day asking about the reporting I was doing and other Guardian journalists were doing on the NSA stories.

This action has created a furor in the UK and parliament is being asked to probe the matter. The Brazilian government has also expressed anger at the way one of their citizens was treated. The Guardian has a live blog covering the reactions.

This latest act was so egregious that even Andrew Sullivan, an ardent Obama supporter and fan of the national security state feels betrayed.

What has kept me from embracing it entirely has been the absence of any real proof than any deliberate abuse has taken place and arguments that it has helped prevent terror attacks. This may be too forgiving a standard. If a system is ripe for abuse, history tells us the only question is not if such abuse will occur, but when. So it is a strange and awful irony that the Coalition government in Britain has today clinched the case for Glenn.

Of course, this is Andrew Sullivan so it is only a matter of time before like a good little boy he finds some reason to scurry back into Obama’s arms and beg forgiveness for his apostasy. But the fact that he concedes, even for a short time, that our warnings of abuse of power were justified is a sign of how much the US and UK governments have overreached with the Miranda detention.

I do not expect the US media to take up this issue too vigorously. They are still smarting from the fact that they are not at the center of the Snowden story and too hostile to Greenwald. They probably welcome anything that hinders his work. Besides, since they are good little supporters of the government, they and their loved ones do not fear being harassed.