A missing piece of understanding why we screwed up in Iraq is because the people planning it compared it to the Panama invasion. I could probably prove it and end this post right now by pointing out a certain Dick C. was Secretary of Defense during the Panama invasion, but there's more to it.
Start with
Grenada: 7,000 US troops attack a small island nation of 100,000 people with 2,000 regular and foreign (Cuban) soldiers. The US wins with 19 US soldiers killed, we take over the island, and it's hard to argue the place isn't better because of it.
Repeat with
Panama: 28,000 troops invade a country of 2 million defended by 16,000 soldiers. The US wins with 24 dead, installs a new leader, and again it's hard to argue the country isn't better off.
Then, enter the establishment's favorite defense liberal, Michael O'Hanlon,
with this gem:
Counting Casualties: How many people would die in an Iraqi War?
By Michael O'Hanlon
Posted Wednesday, Sept. 25, 2002, at 5:37 PM ET A central question about the war in Iraq is the likely cost in terms of casualties. Many Americans who would support an invasion on the assumption of 250 dead might feel very differently if our losses numbered 10 times as many. Unfortunately, such predictions have proven notoriously inaccurate in the past....
Is it possible to make better predictions this time around? It may be, but not with a single number or narrow range....
What do past cases tell us about how a future war conducted largely in the streets of Baghdad might play out....Simply scaling the results of Panama for the size of the Iraqi military leads to an estimate of about 2,000 Americans killed, more than 10,000 dead Iraqi military personnel, and tens of thousands of dead Iraqi citizens. If, however, the only forces that fight hard are the elite—somewhat more than 100,000 Republican Guard, Special Republican Guard, and palace guard forces—extrapolation from the Panama case suggests that losses on all sides might be only one-fourth as great. Such an outcome is plausible. Indeed, U.S. war plans appear to envision targeting only these elite forces, at least at first, and trying to convince the regular conscript army to change sides or sit out the war....
One major wild card remains: the likely consequences of any Iraqi use of weapons of mass destruction....Iraq could also increase casualty levels of U.S. or coalition forces by using WMD against them, particularly its thousands of chemical-filled artillery shells and rockets. But doing so would probably increase casualties by no more than 10 to 20 percent, given historical precedent in conflicts such as the Iran-Iraq war....
The United States and coalition partners would win any future war to overthrow Saddam Hussein in a rapid and decisive fashion. This will not be another Vietnam or another Korea. But casualties could be significantly greater on all sides than in the 1991 Persian Gulf War. The best analogy for what such combat is likely to involve is not Desert Storm, but the 1989 U.S. invasion of Panama—and on a much larger scale. There is a very real possibility that American deaths could exceed 1,000 in number, and several thousand deaths cannot be ruled out. To count on easy victory, as many American proponents of war seem to do, is not only unsupported by the available evidence and by the methodologies of combat prediction. It's also an irresponsible basis on which to plan military strategy in any future war against Saddam Hussein.
(Emphasis added.)
O'Hanlon appears to put the 50% probability level as significantly less than 1000 US dead, and I think we've passed on to a casualty level O'Hanlon thought could be ruled out.
I'll leave a full analysis of why Panama wasn't a good analogy for Iraq to someone else - the minor issues of say, the lack of a religious conflict or that Panama had an elected president and authentic political leadership ready to step in and take power suggest themselves as potential distinctions.
The point is that the range and quality of expertise went from Dick Cheney on the right to this "liberal" military expert whose influence is still felt. I doubt the Cheney people missed the same lesson they also thought they learned in Panama. Can we get some new experts, finally?
As for the anti-war left, though, they're probably not all that interested in this lesson either, as it does point to some uncomfortable examples where invasion by Republican presidents seemed to work okay, whatever the true motivations involved.