My father and my father-in-law, living 10 minutes apart up in Northern Virginia, were very different characters -- personality, habits, likes and dislikes. Suitably cordial towards one another, sure, but palsy-walsy they weren't.

Now, perhaps that's the norm when a couple of strong-willed fellows suddenly find themselves lashed together in an extended family through no choice of their own. But I always had a hunch that their underlying coolness reflected as much as anything their career paths.

One (my father, an electrical engineer) worked his way up through the Department of Defense civilian bureaucracy. The other had been a career Army officer. So each of them was affiliated with a tribe that has about as much use for the other as, say, cobras have for mongeese.

The DoD guys tended to look on their uniformed counterparts as stubborn and self-important. The military guys looked on the civilians as pointy-headed meddlers. Not that there was any serious resistance to the notion of civilian control, but there was a sense among those with scrambled eggs on their hat and fruit salad on their chest that their wisdom and judgment had been validated. To which, the suit-wearers were prone to respond, "Oh, yeah?"

As a gauge of how deep, and troublesome, that great Pentagon divide can be, look no further than the brutal disagreements over how to conduct the war in Iraq, particularly its aftermath.

Secretary of Defense Donald Rumsfeld wanted to streamline things. He prevailed over an Army establishment that favored a much larger invasion force. The Rumsfeld theory worked just fine when it came to kicking Saddam Hussein and company out of their sumptuous Baghdad digs. But -- oops -- the theory had a glitch: Nobody in Rumsfeld's orbit seems to have paid much attention to what would happen after the statues were toppled and the Baathists had skedaddled.

What did happen? Chaos would be the polite word for it, as the nation and the families of service personnel killed since the end of "major combat" have learned to their monumental dismay.

This failure to take prudent steps to keep a brilliantly successful military campaign from being soured by such a long, costly and painful aftermath surely represents grievous folly on the Bush administration's part.

Rumsfeld and his circle seem to have been determined to prove they were smarter than the stick-in-the-mud generals who thought more troops would be needed to keep the lid on after the shooting stopped. Not that they would have been the first DoD civilians to have been driven slightly haywire by the notion that brass hats were conspiring to make their lives miserable. And not that the brass hats sometimes haven't done just that.

What's ironic here is that it wasn't just a few McClellanesque generals who were flashing caution signals. James Fallows, writing in the latest issue of The Atlantic, offers a tale that can only be described as shocking: Detailed planning for the war's aftermath was in fact carried out. If that planning had been heeded, the situation in Iraq today probably would be far brighter. But for the most part, it was ignored.

"Almost everything, good and bad, that has happened in Iraq since the fall of Saddam Hussein's regime was the subject of extensive pre-war discussion and analysis," Fallows reports. "The problems the United States has encountered are precisely the ones its own expert agencies warned against."

The writer, one of the savviest observers of Washington's power politics, dug into a massive study called the Future of Iraq project, carried out by the State Department and initiated in the fall of 2001. There was some concern at State that by planning for a post-war period, the likelihood of a war actually being launched (not a favorite course among the diplomatic types) might rise. But the necessity for such planning won out, and the project went forth in high gear.

What the findings boiled down to was that a regime change in Iraq would mean the potential for massive disorder, which in turn would make the task of devising and installing a democratic successor regime both extraordinarily difficult and dangerous. The key to minimizing that disorder? Enough forces to protect utility grids, prevent looting, maintain security and create a sense of inevitability about the changes to come.

Rumsfeld didn't want to hear it. He apparently thought it was a lot of gloom and doom meant to sidetrack the onrushing war express. And horrors -- if the United States couldn't provide all the forces that State (and some generals) said were needed, then ousting Saddam might have to wait until we could rustle up more international help. We might have needed a "permission slip," as President Bush put it the other night.

What a damning chronicle of arrogant bullheadedness. Getting rid of Saddam was a worthwhile chore. But for bumbling so many of the decisions as to how that chore would be accomplished, Bush and his team should expect judgments to be harsh.

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