Commanding officer

The commanding officer (CO) or commander, or sometimes, if the incumbent is a general officer, commanding general (CG), is the officer in command of a military unit. The commanding officer has ultimate authority over the unit, and is usually given wide latitude to run the unit as they see fit, within the bounds of military law. In this respect, commanding officers have significant responsibilities (for example, the use of force, finances, equipment, the Geneva Conventions), duties (to higher authority, mission effectiveness, duty of care to personnel), and powers (for example, discipline and punishment of personnel within certain limits of military law).

In some countries, commanding officers may be of any commissioned rank, although in others the term only refers to officers in command of units of specific sizes. Usually, there are more officers than command positions available, and time spent in command is generally a key aspect of promotion, so the role of commanding officer is highly valued. The commanding officer heads the command team within the modern military hierarchy.

There are two recurring debates related to military command: the collective command thesis and civil-military relations.

While the commander is an individual, the academic debate centres on whether command is an individual act or a form of a collective. British sociologist Anthony King argued for the emergence of a command collective in Western military forces in his 2019 book Command. Others have argued against King's thesis, stating that it romanticises the collective, that contemporary commanders themselves do not understand their function in this way, or that it may be the case. Still, collective forms of command are less effective in actual combat. U.S. Marine Corps General James Mattis also disagreed with King's thesis: "I disagree if you are trying to do decision-making in boards. The enemy will dance around you".

The civil-military control debate centres on a paradox. The military, an institution designed to protect the polity, must also be strong enough to threaten the society it serves. A military takeover or coup is an example where this balance is used to change the government. Ultimately, the military must accept that it may have to implement a policy decision with which it disagrees.

In the British Army, Royal Marines, and many other Commonwealth military and paramilitary organisations, the commanding officer of a unit is appointed. Thus the office of CO is an appointment. The appointment of commanding officer is exclusive to commanders of major units (regiments, battalions and similar sized units). It is customary for a commanding officer to hold the rank of lieutenant colonel, and they are usually referred to within the unit simply as "the colonel" or the CO. "The colonel" may also refer to the holder of an honorary appointment of a senior officer who oversees the non-operational affairs of a regiment. However, the rank of the appointment holder and the holder's appointment are separate. That is, not all lieutenant colonels are COs, and although most COs are lieutenant colonels, that is not a requirement of the appointment.

Sub-units and minor units (companies, squadrons and batteries) and formations (brigades, divisions, corps and armies) do not have a commanding officer. The officer in command of a minor unit holds the appointment of officer commanding (OC). Higher formations have a commander (e.g. brigade commander) or a general officer commanding (GOC). Area commands have a commander-in-chief (e.g. C-in-C Land Army, C-in-C British Army of the Rhine). The OC of a sub-unit or minor unit is today customarily a major (although formerly usually a captain in infantry companies and often also in cavalry squadrons), although again the rank of the appointment holder and the holder's appointment are separate and independent of each other.

In some cases, independent units smaller than a sub-unit (e.g. a military police platoon that reports directly to a formation such as a brigade) will also have an OC appointed. In these cases, the officer commanding can be a captain or even a lieutenant. The commanders of administrative organisations, such as schools or wings, may also be designated officers commanding or commanders.