Since we're discussing what Yon has said, let me offer some observations of my own. I have just returned from Iraq, where I was a civilian advisor. This is not intended to be in any way the official word of anyone; it's just what I think, having given it rather more than "full time" attention for the last months.
Iraq has essentially three problems to "solve" to become a stable country. These are the Sunni problem, the Shia problem, and the Kurdish problem. By "problem" I mean not that the people are a problem, but that each of the main subsets of the population has a particular challenge that has to be resolved before it can integrate into a successful state. (This is, of course, at a high degree of abstraction -- at the ground level, Shiites and Sunnis may be intermarried, etc.)
The Sunni problem was rejectionism. The Surge has solved the Sunni problem.
That's a fundamental shift in the situation on the ground from a year ago. The gains are -- as Petraeus said -- reversable; that is, it is possible by neglect or malice to create a new Sunni problem. This is chiefly a political responsibility: Congress, State, and the Government of Iraq must ensure they do their part here. (A purely personal opinion: State's operations have improved as much as US military operations have, though they are on a smaller scale as State is on a smaller scale. The PRTs have been a tremendous help, and the current Ambassadors seem to me to be of the first water. The GoI we'll discuss presently. Congress is shameful.)
The Shia problem is armed factionalism. The current violence of this last month and going forward represents the start of the solution to that problem. People alarmed by the violence have missed the story.
Whether it was an incremental success or a humiliating fizzle, hasn't the Maliki government's assault on Sadr-linked Shiite militias operated, de facto, as a highly efficient purge of the Iraqi army? According to Juan Cole, those who heeded calls for defection or who otherwise refused to fight have been fired. ... P.S.: Meanwhile, some 10,000 militia members who did fight on the government's side have reportedly been inducted into the security forces.
What people have not noticed is that JAM is doing essentially the same thing. For quite some time Sadr has been purging JAM of elements that do not obey him. Sadr has said that he will disown members who violate the ceasefire, excepting in self-defense. His proposed truce calls for patience from his members, and comes "after receiving assurances" that his membership will not be targetted if he has them stand down.
Those who continue to fight will be ready prey for the Iraqi security forces, many of whom are from the Badr faction. As Wretchard noted, the de facto arbiter of the Shia situation is al Sistani, who has declared that the militias are not legitimate authorities in Iraq. And -- again, crediting Kaus for his careful thinking about what he reads -- the political debates within the Iraqi government seem to favor this overall movement. (It's also worth nothing that the calls for the JAM to surrender its arms have really been only for heavy weapons -- that is, they could retain small arms, as the Sons of Iraq do.)
The recent violence has been healthy, then. Disaggregation of irreconcilable elements is a key element to our COIN strategy; here we see it happening naturally. The political process appears to be strengthened, and the Sunni blocks are now participating in helping to settle the Shiite question in a manner acceptable to themselves -- as are the Kurds. That sounds like a genuine national coalition forming, one that will accept Sadr as a political figure.
Sadr's own rhetoric, meanwhile, has in this cycle been markedly different from his rhetoric in 2004. It appears that he wants to move into a political role, rather than trying to overthrow and replace the central government.
The Shia problem, then, is not resolved -- but it is in the process of being resolved. That is two of the three big problems in Iraq.
The last one is the Kurdish problem, which remains latent. The resolution of the disposition of Kirkuk is a potential explosive point. It is possible that this problem will be resolved without serious violence; but it is also possible that it will not be.
To this general mixture you should add the tremendous economic progress in Iraq. US military programs -- and PRTs -- are helping to push this economic expansion downward, to tie the whole of the Iraqi population into the gains. This will have an overall beneficial effect on the stability of the nation.
The counterinsurgency work we have done has been highly effective. What remains to be done is largely political, though the US military has an important role as a guarantor of stability, and in the training of Iraqi forces for internal defense. The GoI is internally tremendously complex, as The Long War Journal has covered extensively, but it seems to be improving in its capacity. The provincial powers law, finally passed, should allow for the pushing down of powers to the less-internally-complicated provinces, which should improve local governance and services.
I have very high personal confidence in the mission in Iraq. If it is supported as it deserves to be, I have no doubt that Iraq will become a fairly nice place. It is already better than a substantial swathe of Africa, whose misery passes almost unnoticed -- though note Paul Salopek's National Geographic piece of this month, and confer with your opinions on Iraq.
In return for this last effort, which should require less courage from us than previously, we will gain a permanent ally in the Middle East, and undermine the worst elements of radicalism. We will also protect the lives of millions who have suffered a great deal already: war with Iran, the tyranny of Saddam, and the chaos of this period.
They deserve mercy, and that the strong should stand with and defend them.