Their reasons weren't reasons. I'll admit that starting the war in Afghanistan was a product of political biases, but the political climate in the U.S. after 9/11 played a significant role. People backed the war at home. They dismissed history in favor of going after the Taliban. And then for a while it seemed like we won. Wow! Not even the graveyard of empires can stop us! Obviously it didn't turn out to be that simple.