I'd like to comment on four of 'em -- and amplify something I said earlier.

WM said:
The point to draw here is that different nations have different perceptions about what is an appropriate use of civil police power and what is an appropriate use of military power--for example, I suspect that not every nation has posse comitatus stype statutes and limits. Not every nation has a national police force that may also be called on to perform national defense missions.

So, part of the answer to your question brings us back once again to the old METT-TC discussion. Before we can decide what kinds of policing efforts we may want to conduct and/or train other to conduct, we need to make sure that we are capable of providing the right solution for the target population/nation.
Totally correct -- we too often go blundering in and let our egos get in the way of some considered though about what should best be accomplished for the Nation involved as opposed to what WE would do...

Slapout said the same thing in a different but cogent way:
The first and most important is what is the law that you intend to enforce? How do you intend to communicate that to the target population?
That cuts to the core of the issue and it's imperative that, if we wish for success and attaining said success with the least amount of trauma, those factors be considered.

Wilf said:
Police should never be given military tasks. Internal security forces are another matter, and IMO, should not be military. Their task is "Internal Security" and public order.
I think he's absolutely correct. Combining the three comments quoted above you effectively come up with a need for a Police Force that works to enforce the rule of law for the citizens of the Nation; they "Preserve and Protect" by enforcing the Nation's laws and playing Peace Officer for the population.

By definition, an insurgency and the resultant requirement for COIN operations require a different focus; thus what is needed is that Internal Security element -- it can be called the Paramilitary Police, Field Police Border Police or even the Gendarmerie; the terminology is relatively immaterial but it should have a distinctive name and NOT be simply a branch of the National Police.

The critical point is that it is NOT the 'Armed Forces' or the 'Police.' So far as internal security is concerned, it's goal should be (against all bureaucratic and human nature inclinations) to work itself out of a job -- or, at a minimum, reduce itself to a standby status. There are many advantages to this, not least allowing the local Armed Forces and the local Police to concentrate on their primary roles and not excessively diluting the efforts either or tarring them -- and whoever does COIN work WILL be tarred -- with the internal defense messy, tedious and often dirty work.

Thus it seems to me that ideally a blend of effort on our part might be advantageous. We train the local Army for all its various missions which may include internal defense but with a goal to get that Army out of that mission as soon as it's feasible; USAid reconstitutes their Police Advisory role and structures it to train the local Police as civilian Police Officers -- and another tier, most likely in the case of the US to be provided by the US Army and using Guard and Reserve MP units to train the Paramilitary internal security force -- who should be the lead element in combating the insurgency and only be assisted by the Police and the Armed Forces as required.

Such Guard and Reserve MP units designed to train that internal security force should not be ordinary TOE units simply re-roled. The TOE need to be purpose designed, heavy on NCO and Officer spaces and should actually resemble the TDA structure. Numbered Companies (and even Separate Platoons) under a Separate Battalion HHD. Equipment and uniforms need to be purpose designed-- instead of deploying in ACU, put 'em in 5.11 Cargo Pants and Polo Shirts to emphasize the non-Armed Forces nature of the job. These units should be located in both urban and rural areas in order to get the requisite skill mix. State Police should be targeted for recruitemnt -- and from those States like NY, PA and KY that have actual State Police as opposed to the many that have a State Highway Patrol, those folks only do regular law enforcement in a back up role whereas the SP types do it routinely -- the cultures are very different...

Wilf also said:
...and VERY ANNOYINGLY (sorry to shout) it has just occurred to me that this thread may undermined my "one infantry model" which was one of the corner stones of my doctrine work. Thanks Rob!!
Welcome to the truth, Wilf.

I've never really agreed with you on that. Your basic point is true but the old devil in the details bit arises. Slightly different mindsets -- cultures, if you will -- are created by roles. This can have an effect on performance in very subtle ways and the sheer mechanical differences lead to different training time allocations which in turn lead to significant differences in capabilities based on primary mission parameters.

There was an earlier thread here that discussed whether or not Cavalry or Mech (or re-roled Tank or Arty) could do the COIN mission. I agreed with the consensus; to wit -- yes, they can. They prove that daily. However...

Having been Cav, Mech Infantry, Light Infantry and Airborne Infantry (those two are not synonomous) in both peace and that other stuff I'm firmly convinced that if an Army has to do COIN, Light Infantry can do it better and more efficiently and effectively than the other types. Cav brings elan to the job -- they also bring relatively small units and have vehicles to worry about; the Mech guys also have vehicles and thus can put out only their dismounts (leaving one behind to pass up 25mm in case of need...). In both cases the 25 MPH mentality and concern for vehicles has a slightly detrimental effect on COIN efforts. Do not take that as an insult, it is not. It is, IMO just an acknowledgement of reality -- certainly both Cav and Mech can do things that Light Infantry cannot do. Horses for courses and all that.

Herschel Smith posting on this Board as Danny has complained that the Marines in Anbar are being misused in that they are not using their combat skills but are distributing rations. I don't totally agree with him because you do what needs to be done -- but I do understand and agree with his point. Shortly before my son deployed on OIF 2 and Australian reporter asked one of the kids in the platoon what he was going to do in Iraq; the kid replied "Kill people." The Reporter went into the 'hearts and minds' routine. The Kid replied "Nah, the Army's got other people to do that stuff, we kill people." That's why the Marines and Airborne Infantry are not a good choice for COIN. If they have to be used, they will do the job -- and they will almost certainly do it well. However, they are not the ideal solution for the job, their focus and culture (and recruitment accessions due to that) are just different. They and the Cav tend to be, uh, umm, er, overly aggressive on occasion (The 325 in Fallujah in April 2003 comes to mind...).

All that said, I understand that METT-TC applies and there will be times and places where Cav or Mech are an at least as good if not better choice; we're doing generalities here...

While Cav or Mech units aren't usually the best fit -- totally capable, just not the best fit (I won't even talk about re-roling others) that is not to say that all cannot do the job and do it well and there are, of course as is true with any generality, notable exceptions in all categories that do and have done a superb job -- I'm simply saying that Light Infantry is in most cases the best fit for COIN due in part to sheer numbers -- if the Armed forces have to do it. I say all that with full knowledge of the fact that one does indeed go to war with the Army one has. Reality sometimes means the ideals are irrelevant

Long way of getting back to Wilf's point -- Armed forces can do COIN and many and all types of units have done it well -- but they are not the ideal force for the job; that Internal Security force or element is.