The attacks on the United States on September 11, 2001, have incalculable consequences for domestic politics and world aﬀairs. Reliable predictions about these consequences are impossible. However, it may be worthwhile, even at this early point, to reﬂect on what these acts of violence reveal about the adequacy of our theories of world politics. In what respects have our assumptions and our analytical models helped us to understand these events, and responses to them? And in what ways have we been misled by our theories?