I just read that WWII killed 60 million people and cost less than 1 trillion 1944 dollars. This amount, that translates to 5 trillion of today´s dollars, compares poorly to the current Middle East War involving Iraq and Afghanistan costing USA already around 3 trillion 2008 dollars, but with casualties of less than 200,000 on the "enemy" side (hard to know who the enemy is though) and only 4520 on the American side.
This is what Joseph Stieglitz has to say about this.
These costs (of the current war) are projected to be almost ten times the cost of the first Gulf War, almost a third more than the cost of the Vietnam War, and twice that of the First World War. The only war in our history which cost more was the Second World War, when 16.3 million U.S. troops fought in a campaign lasting four years, at a total cost (in 2007 dollars, after adjusting for inflation) of about $5 trillion (that's $5 million million, or £2.5 million million). With virtually the entire armed forces committed to fighting the Germans and Japanese, the cost per troop (in today's dollars) was less than $100,000 in 2007 dollars. By contrast, the Iraq war is costing upward of $400,000 per troop.
Now considering that Joseph Stieglitz is a Nobel Prize Economist, I am not surprised that he focused his analysis on cost. But all of us can agree that it is actually positive that wars are getting to be, in comparison, so expensive "per death". This, and not moral or religion, may turn out to be the best deterrent policy for avoiding future armed conflict.
It is sad to think that peace may be achieved by parties being unable to afford war but then....so be it. It is a similar situation to a US finally getting to have clean air thanks to very, very expensive oil or global recession. Who knows, maybe God does exist... and he is one stingy banker.