I trust we will not be tempted to descend to the level of today’s terrorists in deliberately killing innocent civilians. —September 12, 2001

For the terrorists, 9/11 was a huge success. At minimal cost, they spun America away from its post-Cold War labors to build a more peaceful global community into a state of permanent warfare against an equally determined and much more elusive enemy. That brought three big consequences. First, invading Afghanistan to get Al Qaeda and the Taliban — a thoroughly reasonable act had it been properly followed up. Second, invading Iraq — an act that had nothing to do with Islamic terrorism and diverted resources from doing Afghanistan right. Third, trillions of dollars spent over the past decade on military, intelligence and domestic anti-terrorist efforts — many of them ill-considered, useless and counter-productive. We now live with over-stretched military forces, a depleted economy, fewer civil liberties, polarized politics and far more enemies abroad. Not a bad score for a few hundred men against the greatest global power ever. We can’t do the past decade over, but can we do the next decade better? Humility would be a good place to start.

Bruce Russett is Dean Acheson Research Professor of Political Science.