RAND Commentary: "Securing America's Ports"

Found here.

Today a great deal of the clothes you wear, the food you eat and the products you use at home and work likely entered America's supply chain packed in large containers on ships that docked at U.S. ports. Unfortunately, terrorists can ship chemical, biological and even nuclear weapons (if they have them) into the United States in the same way. What to do?

Commentary suggests some answers.