I found an interesting post about the Afghan situation over at Brink Lindsey's web site today, which I mostly agreed with, but I found one sentence somewhat discomforting.

Specifically, we have to use our power to keep warlordism in check while the fledgling national government gets established, builds an army, and otherwise develops the capacity to project authority nationwide.

As someone (Harry Browne aside) who considers himself a libertarian, this grated. The purpose of an "army" is not to be used against a nation's own people. If there are warlords in Afghanistan to be quelled, and said entity is a nation, keeping down "warlords" is a job for the police, not an army. Armies (where they are justifiably used at all) are to be used against outside agressors--not against internal subversives.

I have no objection to Acting-President Karzai building up a force to pacify the Afghan nation, but to call it an "army" is to confuse terms, and potentially lay the foundation for a future police state.

To ask a leading question ... was the Union Army a federal police force? What if it had been? And yes, of course that pre-dated Posse Comitatus. But to address your point more directly, did the Union Army's use against internal subversives lay the foundation for a future police state in America? What exactly is the line between a federal police force that meets the threat with armored cavalry, and an army, but a name?

A good question, which raises the issue of whether the Civil War really was a civil war, as the north called it, or the War Between The States, as the Confederacy called it. I tend toward the latter view, myself, in which case, it was the United States using its army against a breakaway region.

What's going on in Afghanistan is truly a civil war (wherein there are two factions struggling for control of the country itself). It would behoove the Afghan government to come up with some version of posse comitatus to try as early as possible to establish the mindset that armies are for defending the nation against external aggression, not to put down its own people, as is too often the case in much of the world.

Most Armies in the world are para-military in nature and are used primarily as bully boys for the regime.

It is only in a few nations where western style freedom and human rights hold sway that the ideal of 'armies deal with foreigners' has taken root.

Using Afghanistan's proposed 'New Model Army' to deal with warlords is a legitimate use of the institution as long as it is for the national interest and not strictly for the current faction in Kabul.

Afghanistan has always been a collection of
warring independent tribes, never a nation-state.
The Army there _is_ the police, as external
and internal aggressors could hardly be told
apart in that environment.