On the Becker-Posner blog.
Posner establishes a sound role for the privatisation of military force in Iraq but worries this might be used for political purposes to understate the death toll. He also believes private soldiers might be more inclined to run amok because there is less authority over them than members of the regular publicly-supplied army.
Becker - yeah you can almost guess it, sees Posner's view as fine but claims that Posner overstates the problems of a private military because competition among firms for a role in Iraq will help guarantee employment of private soldiers who will not be inclined to run amok.
And profit-seeking, self-interested behaviour will again drive the social advantage.