The commanding officer (CO), or if it is an officer in the ranks of general, commanding general (CG), is the officer in command of a military unit. Typically, the commanding officer has ultimate authority over the unit, and is usually given wide latitude to run the unit as he or she sees 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. 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, and in theory, only goes to the best officers. The commanding officer is often assisted by an executive officer (XO) or second-in-command (2i/c), who handles personnel and day-to-day matters and a senior enlisted advisor. Larger units may also have staff officers responsible for various responsibilities.