Michael Chertoff: Well, the bottom line, the accomplishment that was most significant is the fact that we did not have another successful attack against the United States. I think in many ways that’s the ultimate measure. At a somewhat less high altitude, I would say we dramatically changed and increased the security for people coming into the country. We transformed the way we deal with people at the ports of entry, not only bringing 10-print biometrics into effect, but also biographic collection and analysis based on commercial airline data.

We have more robust requirements for crossing our land border in terms of documentation, and even between the borders. You know we built 630 miles of fence, more than doubled the Border Patrol, and according to the reports I got from the Border Patrol just about a month ago, there’s been essentially a two-thirds reduction in the flow [of illegal immigrants] across the border. In some areas where we used to have thousands a day, there are now five or six a day.

Michael Chertoff: In terms of consequence, I would say biological terrorism is the most serious threat. It’s not a threat that I think is imminent, although we’ve had an attack in 2001 with anthrax. It is also one which would not be impossible to fabricate in a short period of time because the raw material for a biological attack occurs in nature or you can just have the know-how. So I would say if it was of high consequence, that worries me the most and I do become concerned.