One of the biggest problems that the US foreign policy has suffered from (for decades) is the fact that one way or another, they become the suppliers of arms to their own enemies.
The pattern is repeating itself in Iraq - how surprising. It seems that sloppy procedures in distributing arms and armor to the "New Iraqi Military" means that an amazing amount of weaponry has likely landed in the hands of the insurgency.
It's hard to say how much of that is deliberate on the part of the US government - nothing about the war in Iraq has been "up front" from day one, why should this be any different?
While the amount of money involved here is quite small - relative to the overall costs of the US occupation in Iraq - it's still quite a lot of money overall, especially when you realize that most of us could retire quite handsomely on the interest income from an investment 1% of $1 billion.
One has to imagine that the Bush administration has spent its time carefully arranging things so that the mess in Iraq remains volatile for years to come - specifically to hamstring the next president of the US. (Especially desirable for the Rethuglicans if the next president is a Democrat - which seems to be a high probability at this time)