I claim that wars are no longer economically useful. It has been said numerous times that entering World War II was what brought the US out of its depression. Sending surplus workers overseas as soldiers coupled with an increase in the production of war materials (everything from uniforms to battle ships) made unemployment virtually disappear. My grandma always said that as long as nations depended upon the military with its arms production and sales, we would never be free of war as an economic factor.
There's something else, too: The innovation that comes out of necessity.
The Wall Street Journal's "The Informed Reader" has read historian Victor Davis Hanson who states that the war in Iraq is not contributing to peacetime technology like earlier wars have. The war in Iraq isn't fought like earlier wars, either, with so many civilian contractors doing what the military used to do for itself (the current ratio is nearly 1:1, according to the Washington Post), and with an enemy that chooses small but important targets, rather going after entire tanks or ships. Unlike earlier wars, the war in Iraq isn't contributing at all to the economy at home. Quite the contrary: The economy is plunging after almost five years of fighting.
I was so sad to see the US and its allies starting the 21st century with such a 20th century (and already outdated) approach. Shouldn't we be done with using soldiers as solutions by now? It looks like maybe that is indeed the case, and not just from a human and humane point of view, but also from an economical and technological point of view.
War has changed. The way wars are fought has changed. Nothing good, not even inventions or discovery, comes out of war. It's time to ignore war as an option for solving or preventing problems, including economic ones.