The "Dollar Auction" has been popularized by Poundstone. It illustrates the futility of war, and some other forms of competition as well. See Wikipedia for a discussion and links:
The basic idea is simple enough. Here's how the auction works: the auctioneer offers a prize, in this case a one dollar bill ($1), to the highest bidder. Bidding starts at one cent. The only catch: the SECOND highest bidder must also pay up, even though they get nothing in return.
It is a great party trick. You may need to prompt people to start the bidding, because most people smell a trick but can't put their finger on it. Someone bids a penny. Someone else bids 2 cents. Pretty soon the bid reaches 99 cents, when the second person realizes he is out 98 cents. So, nervously, he raises the bid to $1. If he wins, at least he is even.
Now things run out of hand. It is always in the interest of the SECOND bidder to up the ante: he looses LESS if he keeps bidding. So it goes. There is no end and the bids keep going up.
The only way to get out in good shape, is to get out as early as possible. Or not play.
War is this way. A nation invests lives and resources to get a 'prize', thinking they can get more than they loose. But there are always other players who want the prize too. Everyone looses everything they spend, but only one player gets the prize they want. So wars go on and on until only all parties but one has exhausted all resources and can't play anymore. Or until one or more player calls it a day and walks away.
That's Iraq in a nutshell. We were told we could win this great prize. It would be cheap and easy. Why not go for it? But we miscalculated: others want the 'prize' too. So the auction is on and quickly runs out of hand. Now, the only thing we can do is leave. Just leave. And sooner is better.
Sure, the insurgents will 'win' something if we walk away. But they will 'win' less than they paid for it. And the longer we play, the more we will 'loose'.
The only alternative is to walking away is for us to literally run Iraq into the ground. Exhaust everyone in the region so, literally, nobody can fight back. We could do this, if we had the will. A few nuclear weapons might do the trick, for example. But what would we 'win' in this case? Nothing. And what would it cost? Way too much. And the 'bad will' generated will last for generations.
Leave, like we did in Vietnam, and in time there will be a chance to make amends and build a new relationship. It is not a good course. It is the only possible course. The idiocy was getting us in this in the first place.