The classification system that governs government secrecy was formalized through executive orders rather than congressional legislation, giving presidents and executive agencies broad authority to determine what information should be withheld from public view. This system has expanded far beyond military secrets to encompass diplomatic communications, economic intelligence, law enforcement investigations, and scientific research, creating categories of information that may remain classified for decades without clear justification related to national security.
The concept of compartmentalization divides sensitive information into discrete segments that are shared only with individuals who have specific operational needs to know particular details, creating information silos that prevent most government employees from understanding the broader scope or implications of classified programs. This compartmentalization can hide the full extent of government activities even from senior officials, while making it difficult for oversight bodies to evaluate the legality, effectiveness, or appropriateness of classified operations.