by Gary Schmitt

About the author: Gary Schmitt is executive director of the Project for the New American Century.

Shortly before getting on a plane to fly to New Jersey from Europe in June 2000, Mohamed Atta, the lead hijacker of the first jet airliner to slam into the World Trade Center and, apparently, the lead conspirator in the attacks of September 11, 2001, met with a senior Iraqi intelligence official. This was no chance encounter. Rather than take a flight from Germany, where he had been living, Atta traveled to Prague, almost certainly for the purpose of meeting there with Iraqi intelligence operative Ahmed Samir Ahani.

To understand the significance of this meeting, put yourself in the position of a terrorist. You work within a small cell of operatives; you are continually concerned about security; and you are about...