In response to your comment about there being no clear plan, the plan is for the additional troops to be a police force. This is right out of the counter-insurgency playbook. Look at successful counter-insurgencies throughout history and they all applied overwhelming force to police the populace, provide security, and prevent insurgent forces from operating freely. This may not be the dashing, clear mission objective such as "take Hill 317" or "defend this bridge until relieved" but again successful counter insurgencies have all used military forces in a police role.

To be honest I do not think 21,000 additional troops will be sufficient to establish the baseline of security necessary for an effective counter-insurgency. It is worth a try however because there is still a possibility it might slow down the escalation of sectarian violence, and if we cannot slow down said violence then nothing else we do will really matter. My key point here is that the additional troops for security purposes is straight out of the counter-insurgency playbook. Watch the movie Battle for Algiers sometime. Granted France eventually lost Algeria but they conducted a successful counter-insurgency against the FLN in Algiers several years prior to the mass uprisings that would eventually lead to independence. If you watch the movie, you will see that the French had a military presense on virtually every street corner. Attacks still got through, but the ability of the FLN to operate freely throughout the city was severely, severely limited.

"I agree that a force addition looks good on paper, but it looked good on paper back in Vietnam, the additional force elements there were just not enough to back out of what turned into a civil war. The same situation is being repeated here."

Except that Vietnam was a conflict between two sovereign nation-states. Granted both states were ethnically linked, but it was an external conflict between two states rather than an internal conflict in one state. In the event that the Soviet Union ever invaded Western Europe, US Special Forces teams would have been deployed throughout eastern Europe to make contact with dissident forces and train, equip and lead them on guerilla operations in the Soviet rear. In Vietnam, the North was doing the exact same thing to the South in preparation of a conventional invasion. The reason why we failed in Vietnam was because we treated the conflict as if the South had a domestic insurgency, rather a foreign infiltration by the North. Granted Iran is playing a part in supporting the Shiite militias, but such support pales in comparison to the guerilla combat operations that the PAVN was conducting in South Vietnam.

"If the 21,000 force commitment fails. What then?"

Then it fails and we try plan B, which I would hope would be a partitioning of the country.

"The US will have no maneuvering "

So are you saying we should hold said 21,000 troops in reserve for deployment in some later, alternative strategy? If not, then how does deploying the troops now limit our ability to maneuver? Look, the NIE makes it pretty clear that withdrawal in the next 12 to 18 months is not an option. In the face of that we either commit our available resources in one last push to make this thing work, or we can immediately turn to other options such as partitioning the country. Either way we will be in this for the long haul. With that in mind, giving the surge a try for 5-6 to months is worth a shot. If the security situation improves then we follow up on such success, if we see no improvement then we pursue the other less favorable options (i.e. partition). In the event it doesn't work, having additional forces on the ground gives us additional flexibility to pursue an alternate strategy. If said troops are not needed for an alternate strategy they can be redeployed, if they are then they are already in country availible for use.

"there will be another crushing morale plummet as US forces will pull out like they did in South Vietnam."

In the likely event that Iraq completely falls apart then such a moral plummet will occur regardless of whether or not the troop surge occurred.

Look, I am very pessimistic about our chances for success in Iraq. I think success would still be entirely possible were there still support for the War. I think the troop surge could possibly work, but probably won't. And I think if the surge fails we should look into a soft partition of the country, which is far less than ideal but will serve our interest of regional stability for better than a failed Iraqi state. In all likelihood I think the failed state is the outcome we're going to get however. The last three years in Iraq have basically been wasted, and I blame the bush administration entirely for that. If we are to succeed we basically need to start from square one. There simply isn't patience among the American people any more for such a long term commitment to Iraq however. I suspect that if the troop surge does not succeed, which is highly probably, patience for the war will be entirely over and a rapid withdrawal will follow leading to the collapse of the Iraqi government and a destabilization of the region. With that in mind what I think we should do is entirely a moot point because there will never be an opportunity to do any of it.

"There is no clear plan for the deployment of the extra 21,000 troops. Most will be stationed in Iraq and the Anbar province. There is no additional task given to these other then blanket security operations which would only mean exposing the troops to more hostile fire."

Yes, it will expose more soldiers to hostile fire. The fact remains however that casualties throughout the Iraq War have been remarkably light given the nature and length of operations we have been conducting there. Over 3,000 deaths and 20,000+ wounded looks horrible on paper, and is certainly tragic, but the reality is that the casualty rates are not yet high enough to have any significant impact on combat effectiveness. If a given Rifle company loses 7 men and has about 25 wounded over the course of a one year tour (these were the casualties sustained in a cavalry company commanded by a friend of mine), there will be very little impact on the overall combat effectiveness of said company. Yes, casualties are bad but so long as they do not significantly impact combat effectiveness they have no tactical or operational impact upon the conduct of a war. They do however further sour public opinion, but at this stage of the game I think the people who will only support a war below a certain casualty threshold have long since stopped supporting the Iraq war.

"At the same time you are dropping an influx of troops into a country where 70% of the population looks upon your forces as occupiers. All that would do is unify the resistance and insurgency against coalition forces even more."

Certainly true, but at the same time the Iraqis are absolutely desperate for some kind of security and increasingly do not care who provides it:

"Now, it's one thing to say that polls show -- American commanders say it -- that most Iraqis, 80 percent of them, do not like being occupied, true. But if you ask any individual Iraqi in any of these areas whether he would rather see more of American troops, they almost invariably say, "Yes," unless they're members of the Mahdi army or one of the militias, because that's what brings calm to the area." -John Burns, New York Times Baghdad Bureau Chief

http://www.pbs.org/newshour/bb/middle_east/jan-june07/baghdad_01-10.html

"It is best I do not use her name. Any Iraqi known to have contact with foreigners is at risk. And security is the only issue that matters now, she says. "Everything depends on it. I am not worrying about democracy, about the economy. The security comes first, and we've lost that." ' -Andrew North, BBC Correspondent, Baghdad

http://news.bbc.co.uk/2/hi/middle_east/6192815.stm

The point is that it really does not seem like the Iraqis really care who provides security, at this point, so long as they don't need to be constantly afraid of getting kidnapped or killed by a carbomb. We can talk about cultural differences and national pride etc. but I know that if I had been living in such conditions for several years, I'd be willing to be under "foreign occupation" if it meant I could stop being constantly afraid for myself and my family. Based upon what the above two, and other correspondents are reporting I'd say that the average Iraqi is in a similar state of mind.

"Either way, what will that force increase do without a clear working plan? Are US forces going to be used to actively suppress the Sunni or Shi'a militias?"

That's my understanding. Due to a lack of US and Iraqi National troops a security vacuum was created in Iraq. The Sunni insurgency was able to take such firm root because of said vacuum. The Sunni insurgency eventually began targeting Shiites, which prompted the Shiites to form militias for their own protection. Reprisal killings sparked reprisal killings and the result is a Sunni-Shi'a civil war on top of the original Sunni insurgency. The idea behind the surge is to provide sufficient US forces to establish joint security sites in the key neighborhoods of Baghdad that will take the place of the various militias. If you can get a (relatively) impartial third party providing security in lieu of sectarian militias, you have a possibility of slowing down or even stopping the escalation of reprisal killings.