Remember "Unfit for Command"? That was the book by career Kerry-basher John O'Neill and rightwinger Jerome Corsi that formed the basis for the SwiftBoaters. The book falsely argued Kerry was unfit to be Commander-in-Chief because he "lied" about his own service record while in Vietnam and about the atrocities committed by others upon his return. The book and the relentless bullshit coverage it received from Joe Scarborough and Pat Buchanan cost Kerry the 2004 election.

"Unfit for Command" is suddenly relevant because Hillary Clinton has made Commander-in-Chief fitness the centerpiece of her new attack on Barack Obama.

"I think that since we now know Sen. (John) McCain will be the nominee for the Republican Party, national security will be front and center in this election. We all know that. And I think it's imperative that each of us be able to demonstrate we can cross the commander-in-chief threshold," the New York senator told reporters crowded into an infant's bedroom-sized hotel conference room in Washington.

"I believe that I've done that. Certainly, Sen. McCain has done that and you'll have to ask Sen. Obama with respect to his candidacy," she said.

Many bloggers have pointed out the political stupidity of Clinton attacking Obama while praising McCain - if she wins the nomination, how could she pick Obama as her VP after trashing him and run against McCain after praising him?

Others have challenged McCain's intellectual fitness to be CiC, including Todd Beeton:

"Certainly Senator McCain has done that?" Really? How? By promising to continue the neo-con bully Bush doctrine for 4 more years? By escalating and perpetuating a tragic war?

But the core argument against McCain's fitness to command is the same as that made by the Swiftboaters against Kerry: not intellect, but character. And McCain's fundamental character weakness is that he is impulsive and arrogant and, when challenged, flies into fits of rage. And the people who know him best worry the most. According to Mark Benjamin,

“I like McCain. I respect McCain. But I am a little worried by his knee-jerk response factor,” said retired Maj. Gen. Paul Eaton, who was in charge of training the Iraqi military from 2003 to 2004 and is now campaigning for Clinton. “I think it is a little scary. I think this guy’s first reactions are not necessarily the best reactions. I believe that he acts on impulse.”

Both Clinton and Obama are secure in their egos, comfortable being challenged by those who disagree with them, and willing to admit mistakes and change accordingly. McCain, just like Bush, cannot stand disagreement, refuses to admit error, and angrily attacks anyone who challenges him.

That is the crucial "threshold" for fitness to command, and the Democrat who makes that argument most effectively is the one who will beat McCain.

Update 1: Matt Stoller agrees:

it is rather remarkable that Hillary Clinton believes that John McCain is capable of leading the military.  John McCain a crazy angry old man whose record suggests he seeks war pretty much all the time.

Obviously Iraq is the overriding problem we're confronting this election with regards to national security, though an attack on Iran is not quite off the table.  But McCain's attitude, that force is correct in pretty much all circumstances, is really quite dangerous.  It's dangerous to the military and it's dangerous to the country, as it will create the conditions for all sorts of wars that are completely unnecessary.

John McCain is a very dangerous man, and if what I hear from Senate sources is correct, he's also probably mentally ill.  What is wrong with Hillary Clinton that she thinks this man is capable of having his hand near the nuclear football?