No period in my career as a government special agent had a more profound effect on me than the early 1990s. At the time, Omar Abdel Rahman, widely known as the "Blind Sheikh," was plotting a campaign of chaos and carnage in New York City. When Abdel Rahman died in prison on Feb. 18, after more than 20 years in U.S. custody, a bloody chapter of U.S. history punctuated by spectacular terrorist plots came to a close....