Mission creep

Mission Creep describes the bureaucratic impulse to expand the original range of tasks in an operation beyond the original charge of the organization. Characteristic of protracted military interventions, it is also apparent in domesic surveillance.

Source

 * Daniel J. Solove. 2011. Nothing to Hide: The False Tradeoff between Privacy and Security. Yale University Press. ISBN 978-0300172317, p. 181.