Military force is another element of power. It provides a nation the capability to impose it's will on another nation through the threat or use of violence. Military force also provides a state the capability to resist another's coercive actions. The types of military forces required will depend on the state's physical characteristics and its enemies' capabilities. A landlocked state has little need for a navy. If a nation's opponent has a strong air force, then the nation should have strong air defenses.
The size and composition of military force available will dictate the types of operations a state may conduct. A landlocked power with no navy will never dominate the seas. A state without an air force or navy today will have great difficulty projecting and sustaining military forces over great distances. A strong army with no ability to move to another area has little impact on foreign policy, except on protecting its homeland.
The technological sophistication of its weaponry versus that of an opponent's will provide a state an advantage or disadvantage in projecting its will. All other things being equal, a state weapons that can kill an opponent's soldiers faster and more efficiency that those of the opponent's has an advantage. Of course, rarely are all other things equal. Technological superiority can provide an advantage, but it cannot guarantee success.
Technology will also affect the state's ability to sustain its forces. Commonality of the civilian and military technological base will enhance logistical capabilities by making it easy for civilian industry to provide military forces the equipment needed.
The location of military forces with respect to the theater of war and the enemy is another component of military power. If the military forces are near their warfighting positioning, their deterrent and warfare capabilities are greater.
The degree of civilian control and willingness to employ military force prescribes the manner in which a state may employ its military power. This point relates to the national will element of power. If the will to employ the military force available does not exist, the military force has no utility. No power results from the simple existence of the military force. Power results from the will to use military power, or at least an enemy's perception of the willingness to do so, and the capability of that military force to defeat all enemy.
Available reserves limit the duration of combat a state can endure. Once all the trained or trainable men and women are casualties, a state cannot continue. A state's manpower pool always serves as a limit on the size of the military force it can raise.
— John M. House
armydefense-policymilitary-power