The people who founded our country didn't trust "standing armies." They were especially distrustful of those who made a career of fighting for the highest bidder.
In colonial times, those fighters were called mercenaries. Today we have a less threatening name for them, private contractors.
I found the article, NO MORE MERCENARIES, by Eric Margolis very enlightening. The numbers were especially interesting.
There are 180,000 to 200,000 US-paid mercenaries in Iraq – or `private contractors’ as Washington and the US media delicately call them. They actually outnumber the 169,000 US troops there. Britain pays for another 20,000. At least half are armed fighters, the rest support personnel and technicians. Without them, the US and Britain could not maintain their occupation of Iraq.
These private enterprise fighters, like the Renaissance’s Italian condotierri, German landsknecht, and Swiss pikemen, are lawless, answering to no authority but their employers.
The world has changed a lot, but making war with private contractors is likely not a good idea.
Then again, lots of people agree this is a problem. Paul Krugman has an interesting article, Hired Gun Fetish, about it in today's NY Times.
As is often the case, people wanting the problem solved, doesn't mean that anything happens.
Perhaps that is why Congress' approval rating has sunk to 11%.