Torture — or enhanced interrogation techniques, if you wish — is not part of the American ethos. It is, in fact, forbidden by law and treaty.

We are, in fact, embarrassed by it, even when it results, as it apparently did, in persuading senior al Qaeda leader Abu Zubaydah to deliver up 9/11 mastermind Khalid Sheikh Mohammed and his accomplice, Ramzi Binalshibh.

Now it turns out that in 2005 the CIA destroyed videotapes of the interrogations three years earlier of Zubaydah and at least one other captive even as the courts, Congress, the 9/11 Commission and defense lawyers were being told those tapes didn’t exist.

Congressional Democrats and the CIA’s many critics are accusing it at the least of obstruction of justice by destroying evidence. CIA Director Michael Hayden insists the tapes were “not relevant to any internal, legislative or judicial inquiries,” although that’s for Congress and the courts to decide. And, it’s also pointed out, the harsher techniques were legal at the time — or so the Justice Department said back then.

The CIA’s rationale for destroying the videotapes, approved by the head of the clandestine division, makes a certain amount of sense from the agency’s standpoint. It wanted to protect the identities of the interrogators to prevent reprisals against them and their families. It wanted to protect its officers from legal risk. And, said Hayden, the tapes no longer had any intelligence value.

As for the great secrecy surrounding both the existence of the tapes and their destruction, the CIA said it informed the leaders of the congressional intelligence committees. But one former chairman said he wasn’t told, another said he was told but only after the fact and another said she was informed and recommended against destroying them.

Clearly, this episode calls out for further explanation. One question is: Did no one at the CIA think that at some time in the distant future, long after all the parties are dead, that these tapes might have significant historical value? Or maybe it’s an episode in our history that no one wants to be reminded of.