The standard conservative line is that it took America two tries and much longer than 6 months to put together a document that has lasted for 250 years. I agree and disagree with this point of view.
I agree that Iraq might have to tear something down and rebuild it. If you do something wrong in software or even social engineering, it is sometimes better to just start over instead of patching the system you have built poorly. If the constitution is not perfect then I would be okay with starting over, though I would not be okay with it not being perfect.
The second part of the argument I do not agree with fully. 250 years ago they did not have telephones, Internet, or any other grand constitutions to start from. They had several supporting documents, a couple revolutions, and some basic philosophy. The Iraqis have much more than that. There is a wealth of information on how to build a great and prosperous nation and it is getting better everyday.
The Iraqis are much further along in the constitution development life cycle than we were 250 years ago. They have many examples to choose from. Heck, if they need the help we can write one for them.
They also have the advantage of modern communications, although that advantage might be limited in a war zone like Iraq.
Thirdly, they are not riding in by horses, but by armored convoys that probably cover much more ground than the early horse and buggy covered.
Basically, since logistics and constitutional practices are much further along than they were 250 years ago, the Iraqis only have their selves to blame if they screw this thing up and have to redo it. I expect a lot more than what they are giving us.
To the Iraq people all I have to say is this: Americans fought and died for your freedom, maybe that does not mean anything to you, but to me it means quite a bit. Get you crap straight or we will let you fight it out amongst yourselves, because Americans really can be heartless bastards when we want. If you screw up the chance that we gave you, I could really careless what happens to you, your people, or you country.