Do we really need to be able to predict war? (Kelsey Hunter, Week 6 Dialog)

The other day in our brief discussions with smaller groups, we talked about the idea that Constructivism doesn't try to predict what will happen in the world system. Instead Constructivists "forecast." From my Economics of Business Decision Making class I've learned that forecasting is wrought with unpredictability and uncertainty. Our small group brought up the idea that Constructivists were "copping out" by claiming that they can't predict anything in the international system. But I disagree, the other theories predict that there will either be war or peace based on the way states behave in either the Realist or Liberal view of the world. What I want to know though is do we really need to predict war or peace, and is this actually realistic? I would agree with the Constructivists that trying to predict anything with any certainty is unrealistic because the world is ever changing and our actions and our interactions with other states can change at a moments notice. For example, on September 10th, 2001, would anyone really be able to predict with certainty that the U.S. and many other states around the world would be engaged in a war on terror and specifically a war in Afghanistan? Perhaps there were certain signs that U.S. foreign policy was becoming more prone to war, but the actions of a group of individuals (not a state) significantly altered the course of U.S. foreign policy in a single day. So, I feel that it is unrealistic to try to predict war, because the world is an uncertain place. Should we predict war or peace is another story, but my answer there would be no, we don't need to predict war or peace. Predicting war is so pessimistic and creates fear among states- ie. the Cold War. Predicting peace creates false hopes and doesn't take into account the realities of uncertainty, ie. the League of Nations. The reason I like the Constructivist point of view is that it seems more practical to look at the interactions of states and the actions of states and maybe forecast with uncertainty than predict with certainty.