Salon's Glenn Greenwald writes in great detail about MSNBC anchor Keith Olbermann's apparent reversal on the FISA law.

In January, Olbermann unleashed a Special Comment aimed at Pres. Bush and the law, saying, "Illegal and unjustified spying on Americans under this flimsy guise of looking for any terrorists who are stupid enough to make a collect call or send a mass email."

On Wednesday night, as Greenwald writes, Olbermann's, "blind devotion," to Obama led him to describe, "Senator Obama also refusing to cower even to the left on the subject of warrantless wiretapping."

"Are we hoping for a Fox News for Obama, that glorifies everything he says and whitewashes everything he does?" asks Greenwald.

Obama's support of the FISA bill and subsequent blogosphere backlash is detailed here.

Last night, after Countdown aired, Olbermann issued a response, by way of the Daily Kos, to Greenwald and others.

Olbermann explained it was John Dean last week when he was a guest on Countdown who, "quelled any anger simmering beneath my surface," when he explained why Obama supporting FISA was okay.

"I don't know much about Mr. Greenwald and I didn't read his full piece," writes Olbermann. "I do think Mr. Greenwald's suggestion of some kind of betrayal on my part is simplistic and childish."

And today — Greenwald responds.

Greenwald, who writes, "a John McCain presidency would be disastrous for this country," and who has written such books as "A Tragic Legacy," takes exception with Olbermann's explanation.

"Despite his having packed his response with substance-free invective, I'm going to keep the reply as dispassionate as possible because I'm not interested in engaging in some personality-driven spat of the type that he seems to enjoy," writes Greenwald, who then proceeds to write 2,000 words on the matter.

He concludes: "But basic honesty and adherence to one's core political values compels criticism for what Obama is doing here, and it's just distasteful and destructive — not to mention dangerous — for people to invoke patently false rationalizations in order to excuse or support what he's doing."