Detaining or detention primarily refers to which group of individuals?

Detaining or detention primarily refers to any individual not subject to the Uniform Code of Military Justice (UCMJ) because it encompasses a broader scope than just military personnel or specific groups. This includes civilians, contractors, and others who may be present in a military environment. The key aspect of this choice is that it recognizes the authority and responsibilities of security forces in handling various individuals, regardless of their military status.

Military personnel are already subject to UCMJ, thus their detention is governed by a different set of regulations. Civilians and contractors, while they could be detained, are specifically addressed in the context of being outside the military justice system. Detainees in military custody might refer more specifically to individuals in a controlled environment, often following a high-level legal or security determination. Therefore, "any individual not subject to UCMJ" captures the essence of detention as it pertains to the responsibilities and jurisdiction of security forces in diverse operational scenarios.