Have you ever considered full employment as a means to properly measure the cost of wars? Tolerating unemployment may indeed lead to pro-war sentiments.  Fighting wars requires using resources to produce weapons, feed soldiers, provide transportation. Thus, maintaining chronic unemployment is a powerful economic incentive for war. In a fully-employed economy, i.e., an economy where a full employment goal is constantly and successfully pursued, the need of resources for a war would compete with other demands on resources. War would inevitably entail a reduction of the standard of living. In a fully-employed economy, war costs become explicit and they can better be weighted in with any alleged benefits of fighting.

If you think wars in Iraq and Afghanistan were a gigantic waste of money, chronic unemployment in peacetime may be even worse! War raises output and unemployment is not an efficient allocation of our resources.

Wars raise output only to consume it in battlefields, with no real improvement in per capita standard of living. But the same fervor we use to point to the waste of resources (not speaking of human tragedies) resulting from wars, should equally be applicable to any rate of unemployment above zero.  Unemployment entails a similar, and in almost all cases effectively in greater magnitude waste of output that is not produced in the first place.