imperium in imperio

Calque of Ancient Greek κράτος εν κράτει (krátos en krátei).

imperium in imperiō n (genitive imperiī in imperiō); second declension

1. A state within a state, inclusive of deep states or other forces which operate with sovereign-like impunity within a polity
   • 1872, James Legge translating Confucius as The Ch‘un Ts‘ew, Prolegomena, Ch. iii, p. 116:

     ...the system of presiding chiefs... was most anomalous,—an imperium in imperio,—and weakened the bond of loyal attachment to the throne. Of what use were the kings of Chow, if they could not do their proper work of government, but must be continually devolving it on one or other of their vassals?

• status in statū

• "imperium in imperio" in Black's Law Dictionary, 2nd ed.