Less than a year ago, I participated in a seminar at a public agency in Washington where we spent time trying to imagine the worst possible terrorist calamity that could occur in the United States. Two basic scenarios were presented. One individual suggested that the Chinese would launch a nuclear attack using ballistic missiles. Everybody thought that scenario was the most likely. My suggestion was that we would be hit by a much lower-grade attack by Islamic fundamentalists on American soil. Moreover, I said, our response would be constrained because we would not want to offend the sensibilities of Islamic fundamentalist leaders and their groups. They were already establishing a demographic base in both the United States and Europe and would argue strenuously against any kind of effective response.

Unanimously, the other participants responded, "This could never happen." First, they said, fundamentalists would never attack us here. Second, they knew that the U.S. would respond so horrifically if such an event did occur that we would wipe them off the face of the earth. Finally, they said, fundamentalists had no real motive to pull anything like this off.

These were very smart people, dedicated public servants. They had no axes to grind. They weren't arguing the case for one group or another but were sincerely trying to evaluate America's situation as far as international terrorism was concerned. Yet I walked out of that meeting and e-mailed a friend, "We're doomed. It is beyond the official imagination of this government to conceive that we can be attacked. There is an underlying assumption that we are such good people that nobody would ever want to attack us here."

Since September 11, 2001, everything has changed - and yet nothing has changed. The only difference between February 26, 1993, and September 11, 2001, is that there are 3,500-odd more people dead. We are still vulnerable. We have only a short time to prevent the next chapter from unfolding. This is the most important battle of our time. Today we still have a window of opportunity to prevent further devastation. But the window won't be open for long.