Which agency cannot be represented by the Secretary of Defense in industrial security services?

The Central Intelligence Agency (CIA) cannot be represented by the Secretary of Defense in industrial security services primarily due to its distinct status and operational structure within the U.S. government. The CIA operates under its own unique security protocols and regulatory framework, necessitating a level of independence from the Department of Defense. This separation is crucial for maintaining the agency’s ability to conduct intelligence and operational activities without overlap or undue influence from defense policy and priorities.

In contrast, the other agencies listed — the Department of Commerce, Department of Justice, and Department of Labor — engage in industrial security services under the umbrella of national security and defense. They typically coordinate more closely with the Secretary of Defense on matters pertaining to industrial security, which involves safeguarding sensitive government contracts and information essential to national security. Thus, the CIA’s independence in matters of intelligence and security ensures it is managed distinctly from the framework defined by the Secretary of Defense. This delineation of responsibilities highlights the CIA's specialized role within the intelligence community.