Whereas InSec reported to the Ministry of Internal Security and the Mental Hygiene Police was a part of the Office of Public Information, NavSec was a military organization which depended from the Ministry of War. Units of the People's Marines were usually assigned to Naval Security as its intervention forces. NavSec's mission was to intervene with military forces in support of the Havenite government against any domestic threat to its power. Within the People's Navy, NavSec was also responsible to prevent the leaking of classified information to unauthorized personnel and to supervise the general readiness of military units.
Naval Security enjoyed a better reputation within the Havenite population than any of its fellow security agencies. (HH3)
Following the murder of Secretary Walter Frankel in 1904 PD, Secretary of War Elaine Dumarest offered Hereditary President Sidney Harris to use NavSec against the Citizens' Rights Union. The proposal was rejected.
The attack that killed President Harris and the other leaders of the Havenite government was masked by the conspirators as an "unscheduled training mission" conducted with authorization from NavSec. (HH3)