The U.S.-led invasion of Iraq in 2003, you may recall, was dubbed Operation Iraqi Freedom.  Eleven years and over 100,000 civilian deaths later, the name is dark comedy.  The replacement Shiite-dominated government is a close ally of the Iranian theocracy, and is now immersed in a new civil war against a would-be Sunni caliphate, the Islamic State of Iraq and Syria

When the original supporters of Operation Iraq Freedom urge further military action, it’s rhetorically easy to mock them for their past failures.  But is it reasonable?  Sure, mistakes were made.  But shouldn’t arguments about additional military action rest exclusively on the world we actually face right now?  In economic terms, harping about past failures sounds like the sunk cost fallacy writ large.  What’s the use of crying over spilled blood?

Here’s the use: Past failures predict future failures.  Most Americans thought Operation Iraq Freedom was a good idea at the time.  American hawks were especially hopeful.  Both groups’ predictions turned out to be deeply mistaken.  For starters, their failures remind us that human beings are bad at predicting wars’ long-run consequences.  More importantly, though, hawks’ greater failures remind us that contemporary hawks are especially bad at predicting wars’ long-run consequences. 

You could say, “We should focus on experts’ arguments, not their track record.”  But this is the height of naivete.  No one has time to thoughtfully evaluate experts’ arguments on more than a handful of issues.  And even if you did have years of free time on your hands, the truism remains: past failures predict future failures.  Discounting experts with bad track records is as reasonable as deleting spam emails unread.

If we held every proponent of every war to these unforgiving standards, we’d fight very few wars.  Some wars work out well, but singling out such wars in advance is extraordinarily difficult.  Hawks may take this as a reductio ad absurdum of my position, but they’re the ones being absurd.  If you can’t calmly say, “We can be extremely confident that killing lots of innocents in the short-run will vastly improve the world in the long-run,” you shouldn’t kill lots of innocents.  And killing lots of innocents is what every modern war entails.