Security Executive Agent Directive 1: Security Executive Agent Authorities and Responsibilities (Effective: 13 March 2012) [open pdf - 1MB]
"This Directive consolidates and summarizes the authorities and responsibilities assigned to the Director of National Intelligence (DNI) in the role as the Security Executive Agent (SecEA) responsible for the development, implementation, and oversight of effective, efficient, and uniform policies and procedures governing the conduct of investigations and adjudications for eligibility for access to classified information or eligibility to hold a sensitive position. Nothing in this Directive shall be construed to limit the DNI's legal authorities."
Security Executive Agent Directive 1
U.S. Office of the Director of National Intelligence: https://www.dni.gov/