Prevention of WMD through maritime security

A speech on "Preventing Weapons of Mass Destruction (WMD) Terrorism in the Maritime Supply Chain" found here:

Reducing WMD Terrorism Risk through a Layered Defense-in-Depth

Defending the United States and our international partners from a covert nuclear or biological attack by terrorists presents many operational and technical challenges. Since we cannot afford to fail in this mission, we must embrace a strategic approach capable of reducing this risk to its absolute minimum. We also know that no matter how effective, no single capability can provide a fail-safe protection from a WMD terrorist attack.

To reduce our collective risk from WMD terrorism, we must develop with our partners a layered defense-in-depth. A layered defense, or defense-in-depth, is a strategic concept employed in a diverse range of security-related fields, from missile defense to cybersecurity. Its central premise, especially applicable to combating WMD terrorism, is that no single layer, or capability, can provide us with sufficient protection against a determined and adaptable terrorist adversary. However, a terrorist or a terrorist facilitator who has to overcome multiple defenses in the course of his attack plan is more likely to be detected or deterred, or to fail during the attempt.