Sec. 4.4. Access by Historical Researchers and Certain Former Government Personnel.
(a) The requirement in section 4.1(a)(3) of this order that access to classified information may be granted only to individuals who have a need-to-know the information may be waived for persons who:
(1) are engaged in historical research projects;
(2) previously have occupied senior policy-making positions to which they were appointed or designated by the President or the Vice President; or
(3) served as President or Vice President.
https://www.archives.gov/isoo/policy-documents/cnsi-eo.html#three