"Since the end of the Cold War, Soviet aggression had been replaced by a number of particularly venomous threats, from Timothy McVeigh to Osama bin Laden"

This quote by Barbara Olson is referring to the shift in worldwide security risks considering that the end of the Cold War. Throughout the Cold War, the main risk was Soviet hostility, however since then, the world has seen a variety of different, more hazardous risks. Timothy McVeigh was an American domestic terrorist who was responsible for the 1995 Oklahoma City battle, while Osama bin Laden was the leader of the terrorist group al-Qaeda, responsible for the September 11th attacks in 2001. Both of these people postured a lot more serious danger than the Soviet Union ever did, and their actions have actually had a long lasting impact on worldwide security. Olson's quote is a reminder of the altering nature of security dangers in the post-Cold War world, and the requirement for watchfulness in the face of these new risks.