Here is a howler from Paul Krugman:
The fact is that war is, in general, expansionary for the economy, at least in the short run. World War II, remember, ended the Great Depression. The $10 billion or so we’re spending each month in Iraq mainly goes to US-produced goods and services, which means that the war is actually supporting demand. Yes, there would be infinitely better ways to spend the money. But at a time when a shortfall of demand is the problem, the Iraq war nonetheless acts as a sort of WPA, supporting employment directly and indirectly.