When's the last time Congress approved of a war? How about the American people? Maybe that first six months of Afghanistan? Maybe...

The President doesn't need approval for military action, and hasn't for decades. In a not so subtle way, we elect Presidents to make decisive decisions, such as when to engage in a conflict.

And to address your question, the cost is probably neutral so far. We'll need to replace many of the munitions, but we do that anyway. The loss of life is probably the most costly aspect of this conflict thus far.