Defense analysts and policy makers now refer routinely to the challenges of operating in a “gray zone” of conflict, which coincides with recent scholarly efforts to analyze more rigorously conflicts short of traditional coercion or war. Yet despite its frequent contemporary usage, the term gray zone does not seem to describe anything new.
"Tactics of Strategic Competition,"
Naval War College Review: Vol. 70
, Article 4.
Available at: https://digital-commons.usnwc.edu/nwc-review/vol70/iss3/4