Is anyone else as concerned about the 'Private Military' we have spawned?

Blackwater, alone, accounts for more troops in Iraq (180,000) than our military (160,000). These are men trained by our military, most ex-military mercenaries....we pay these forces about 6-9 times what we pay our own troops! WE hire them for KP, security, you name it, it is pieced out now at tremendous costs. When a nation has a military group (s) in this case, (Blackwater is but one), who do they answer to? IF a President, or general were to have the funds, are we setting ourselves up for an overthrow of our government as we know it? Mercenaries go to the highest bidder, not necessarily American! It would seem that many, many wrong turns have been made by this administration and others before it...we have a real problem when mercenaries outnumber our own soldiers....This has happened in far too many countries to ignore it...it can happen here, we are NOT immune to a coop! I suspect I will get blasted for this question, but I am genuinely concerned at this point, not without reason.