Wiktionary
counterpower
n. A political power capable of challenging and potentially removing the power of another. Usually used to refer to the ability of 'have-nots' to combat the 'haves'. The word can be used to describe countervailing forces both within (see quotation 1) and between (see quotation 2) states.
Usage examples of "counterpower".
They were the maritime counterpower to Ancient Egypt and its deeply entrenched land-based empire.