ANOTHER MISTAKE AT GUANTANAMO…. Describing the detainees at Guantanamo Bay, Dick Cheney said last week, “[N]ow what’s left, that is the hardcore.” This is consistent with the line from the Bush White House, which has always maintained that those held at the facility are “the worst of the worst.”

And yet, there’s ample evidence to the contrary. Since November, at least 24 detainees — roughly 10% of the population of the detention camp — have been found to have been wrongly held by the Bush administration. The latest painful story is that of Haji Bismullah.

For nearly six years, Haji Bismullah, an Afghan detainee at Guantanamo Bay, has insisted that he was no terrorist, but had actually fought the Taliban and had later been part of the pro-American Afghan government.

Over the weekend, the Bush administration flew him home after a military panel concluded that he “should no longer be deemed an enemy combatant.”

Which is to say, Bismullah hadn’t done anything wrong. He was identified as a terrorist by Taliban collaborators who wanted his position as an official of the pro-American regional government in Helmand Province, and that was enough to keep him locked up. (Once taken into custody, one of his accusers stole his car.)

It gets worse.

At Guantanamo, Mr. Bismullah insisted he was innocent. He told military officials to contact his brother to vouch for him. The officials concluded that the brother was “not reasonably available” as a witness. At the time the brother, Haji Mohammad Wali, was the chief spokesman for a pro-American provisional governor who regularly gave news conferences, legal filings say.

In 2006, the brother filed a sworn statement with Guantanamo officials. Mr. Bismullah and his whole family, he wrote, “fought to drive the Taliban out of Afghanistan.”

Mr. Bismullah, he added, had a wife and three children, including a son born while he was in Guantanamo. “The boy,” he wrote, “has never seen his father.”

The United States kept this man detained for nearly six years. He was on our side, a fact that our allies were prepared to corroborate — and did corroborate in 2006.

The mind reels.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.