How is combat power best defined?

Combat power is best defined as the total means of capabilities at a given time. This definition encompasses not only the number of weapon systems and personnel available but also their readiness, effectiveness, and the overall organizational structure that enables them to operate. It focuses on the current capabilities, integrating factors like firepower, mobility, command and control, and sustainment.

Understanding combat power in this way is crucial for military planning and operations, as it allows leaders to assess their forces' current strengths and readiness to engage in battle effectively. This definition highlights that combat power is not static; it can change based on the situation, logistics, morale, and a variety of other factors.

The other choices, while related to military operations, do not encapsulate the full essence of combat power. For instance, the capability to conduct long-term operations refers to operational endurance, and the availability of resources for training concerns preparation rather than immediate combat effectiveness. The ability to deter enemy advances pertains more to strategic posture rather than a comprehensive assessment of combat power at a specific time.