The landmark five-year, US$40 million Senate investigation of the official US torture regime at the height of the War on Terror elicits something that might be described as a horrifying sense of familiarity.

While the sane among us knew the CIA had waterboarded far more than the three people once claimed by the likes of Dick Cheney, most would have been unaware of the prevalence of other arcane and humiliating practices such as 'rectal hydration' and 'rectal feeding' that interrogators used to exert control over suspects. Still, can we be surprised by anything at this point?

This is not to suggest that the new report is anything less than a vital document in need of continued parsing and discussion; it is to say that the reaction should not now be one of shock but of confirmation of a fairly troubled period in American foreign policy.

The question now is what will be the legacy of this report and of the illiberal practices and official cover-up it revealed? Many Republicans see the report's release as little more than an attempt to continue embarrassing former President George W Bush (have we not yet reached some sort of upper limit on that count?) and are no doubt weary of their own continued associations with the deeply unpopular Texan in power at the time of the documented events.

That thinking seems a bit of a stretch, given the Republicans have just dominated mid-term elections and we are still two years out from the next opportunity for ploys such as these to have any real currency.

There is also the fact that the broad US population have until now shown no great concern over the use of torture, even as it has frequently been shown to have either little efficacy or be outright counterproductive (by producing false information).

For his part, President Obama said the report's findings were in line with his belief that the CIA's practices under the War on Terror 'were not only inconsistent with our values as a nation, they did not serve our broader counterrorism efforts or our national security interests'. We should also remember that Obama ordered an end to the practices outlined in the report fairly quickly after replacing Bush.

But how does this square with the fact that Obama and his administration largely complied with CIA requests to stall the release of the information until now, and that it saw the light of day mainly due to the determined efforts of Californian Senator Dianne Feinstein, and then only in the form of 500 pages of a much larger and still classified 6700-page investigation?

In the age of ISIS, there is some argument to be made that suppression of the findings would protect American lives from any terrorist backlash, but official US secrecy and denial of wrongdoing is surely just as galling to its enemies, particularly those who have first-hand accounts of it.

Clearly there is still a lack of the promised openness and transparency around the CIA and other arms of the US national security apparatus where Obama is concerned. And with the President's time in charge fast running out and his focus shifting to matters such as immigration and climate change, there is a risk that the culture has not been changed so effectively as to outlast any sudden and dramatic threat to US national security in the future.

Let's hope somebody has the good sense to drag up this report — and even petition for the release of its full contents — should the undesirable ever happen.