Add to those pressing for a full investigation of Bush-era detention policies former U.N. Ambassador Thomas Pickering and former FBI director Bill Sessions. In an op-ed piece in this morning's Washington Post, the former officials, both of whom served under George W. Bush's father, urge President Obama to appoint a presidential commission to ferret out the details of who authorized what in the sad Bush policy of detainee abuse.

Investigations by Congress and other bodies have shown that, since the Sept. 11, 2001, attacks, government officials have encouraged and acquiesced in prisoner abuse by U.S. personnel, and detainees have been transferred to countries that are known to torture. In many cases, the perpetrators of abuse and torture were given the support and encouragement (tacit or explicit) of their superiors, possibly as high up the chain of command as the president himself.

The two praise Obama for ordering Guantanamo closed. "But it is only a first step. . . . We must understand how we got where we are today to ensure that we correct our past mistakes and change our policies going forward."

There is no doubt torture took place. Pentagon official Susan Crawford bluntly acknowledged as much in an interview with Bob Woodward earlier this year.

The Red Cross made the allegation in its confidential report to the Bush administration on the treatment of 14 so-called high value detainees while they were held at clandestine CIA prisons, as Mark Danner reported in The New York Review of Books. This piece is illuminating in that it reveals some of the "sophisticated" interrogation techniques the Bush administration felt had to be kept secret to prevent al Qaida operatives from preparing for them. The chief one: wrapping a towel or clamping a collar around a detainee's neck, then using the extra leverage that would give to slam the detainee's head into the wall. Exactly how does one prepare to resist that?

Michael Hayden, when he was CIA director, downplayed the extent of such abuse by saying only three detaineess were subjected to waterboarding, which until the Danner story came out was the only specific interrogation technique widely discussed. But no one has addressed how many underwent the "collar beating" treatment. And no one has answered whether the use of that technique had the approval of someone in Washington.

Maybe someone ought to.