Announcements by President Obama that his government was to ban torture, honour the Geneva conventions and close down Guantánamo Bay were greeted with delight by opponents of these notorious relics of the Bush era.

Maybe it was simply relief, a gratitude for small mercies. But looking at how much has actually changed, maybe it was naivety.

Much was made, rightly, of the unprecedented ruling in the English high court last week when Lord Justice Thomas and Mr Justice Lloyd Jones made it abundantly clear they wanted evidence to be disclosed of how Binyam Mohamed, the former British resident held in Guantánamo Bay, was tortured.

But they could not order disclosure, they added, because of claims by the foreign secretary, David Miliband, that the US had threatened to stop sharing intelligence with the UK, its closest ally, if the information – obtained from US officials – was released. And that, said Miliband, would "cause real damage to the national security and international relations interests of the United Kingdom". Lives may be put at risk, he claimed.

As a result material was withheld in Mohamed's case not because the material itself was sensitive, but because America was sensitive about it.

The documents themselves could not possibly be described as "highly classified US intelligence", the judges said, and concluded: "If the information ... which we consider so important to the rule of law, free speech and democratic accountability is to be put into the public domain, it must now be for the United States government to consider changing its position or itself putting that information in the public domain".

Of course the Obama administration would change its position – many assumed – and Miliband's claim that a post-Obama US was unmoved was met with disbelief.

But the valuable lesson to be learned from recent events is that, in the case of American policy – whether under Obama or not – respecting human rights and the rule of law does not necessarily involve openness.

Promising not to torture detainees does not necessarily mean releasing documents detailing the sins of the past.

It was this realisation that led to a palpable sense of disappointment when Obama's government came to the aid of the beleaguered Miliband. The day after the high court judgment, the British foreign secretary told the House of Commons that the US national security council "reaffirmed the longstanding position concerning the importance of protecting sensitive national security information and preserving the longstanding intelligence-sharing relationship between our two countries".

Then on Monday, Obama's justice department repeated the Bush administration's policy of citing "state secrets" to prevent the release of evidence concerning extraordinary renditions – specifically, how Jeppeson Dataplan, a subsidiary of Boeing based in San Jose, California and Crawley, West Sussex, allegedly helped the CIA transfer them to countries where they faced torture.

Bush's justice department warned against revealing the CIA's methods in holding and interrogating terrorism suspects, as well as details of the co-operation of foreign governments. Obama's justice department says the same.

The new US attorney general, Eric Holder, had instructed officials to review the "state secrets" policy, a justice department spokesman said: "It is vital that we protect information that, if released, could jeopardise national security."

Now where have we heard that before?