someone already mentioned Jeremy Scahills book,
here is a link blackwaterbook

he mentioned when he was interviewing a cop in new orleans
an unlicensed car sped up, four guys with machine guns jumped out and
asked the cop something and sped off.. Turns out when he talked to these guys later they were Blackwater guys, and they were deputized by the governor to maintain order (in their words they were there to shoot looters).

Blackwater was charging $950 US per day, per person.. and yet there was a lot of flack about the measly Fema $2000 debit cards people received being a waste of money. (in fact they were the most useful expenditure)

according to Scahills interview theres something like 40,000 Blackwater guys in Iraq, providing security and yet they are answerable to no laws since they are not part of the military
(on one occasion when Bremer tried to arrest on of Al Sadrs deputies in 04, you had a situation when a marine guard in Najaf was asking a Blackwater guy for permission to open fire)

whatever the laws that may be in Iraq, they havent been enforced.
So far with so many Blackwater guys in Iraq, only one has been charged with knifing another Blackwater employee, theyre either a bunch of ANgels or something stinks.

private armies, (no need to worry about the political ramifications of having a draft) secretive and answerable to no-one.

war - what is it good for?
its good for business.