Measuring Security in Terms of 'Perimeters'.

• Author: Book, Elizabeth G.
• Position: Brief Article

"Secret Service agents work under a concept called perimeter security," said Dario Marquez, a former Secret Service agent who served on the security details of Presidents Nixon, Ford, Carter and Reagan. He is now chief executive officer of a security-staffing firm called MVM Inc, located in McLean, Va.

He explained that perimeters of security are used to keep "assets," such as buildings or dignitaries, secure from adversaries.

The first perimeter of security is intelligence, said Marquez. "Knowing the adversary, his strengths, weaknesses and his methods of operation are important. The best way to gather intelligence is to have sources inside the adversarial operation, penetrating the group," he said.

Intelligence information assists with the second perimeter of security, which is access control. "Access controls are your countermeasures," he said. Marquez explained that security officials must control access to the nation's borders and question the types of identification that Americans use to travel.

The September 11...