An error does not become truth by reason of multiplied propagation nor does truth become error because nobody sees it.

Better to trust the man who is frequently in error than the one who is never in doubt.

Air travel survived decades of terrorism including attacks which resulted in the deaths of everyone on the plane. It survived 9/11. It'll survive the next successful attack. The only real worry is that we'll scare ourselves into making air travel so onerous that we won't fly anymore.

Airline travel is hours of boredom interrupted by moments of stark terror.

I knew from the beginning that privacy was going to be a huge issue especially with regard to applying Total Information Awareness in counterterrorism. Because if the technology development was successful a logical place to apply it was inside the United States.

To a considerable extent we are faced by a technology arms race with terrorists. The communications revolution has made it easier for terrorist groups to reach out to vulnerable individuals with their violent extremist ideology and propaganda. It has also facilitated fundraising recruitment and training.

The only protection as a historian is to institute a process of research and writing that minimizes the possibility of error. And that I have tried to do aided by modern technology which enables me having long since moved beyond longhand to use a computer for both organizing and taking notes.

Countries across the world are taking action now to help them track paedophiles and terrorists who abuse new technology to plot their horrific crimes.

This is technology that will not go away. And to risk it moving into the hands of a terrorist group like al Qaeda or to other focused enemies of the United States would have tragic consequences.

We're in a new world. We're in a world in which the possibility of terrorism married up with technology could make us very very sorry that we didn't act.