Reserve officer

A military reserve force is a military organisation composed of citizens of a country who combine a military role or career with a civilian career. They are not normally kept under arms and their main role is to be available to fight when a nation mobilises for total war or to defend against invasion. Reserve forces are generally not considered part of a permanent standing body of armed forces. The existence of reserve forces allows a nation to reduce its peacetime military expenditures while maintaining a force prepared for war. It is analogous to the historical model of military recruitment before the era of standing armies.

In some countries, such as Canada, United States, Spain and the United Kingdom, members of the reserve forces are civilians who maintain military skills by training, typically one weekend a month. They may do so as individuals or as members of standing reserve regiments, for example the Army Reserve of the United Kingdom. In some cases a militia, home guard,or state guard could constitute part of a military reserve forces, such as the United States National Guard, the Norwegian Home Guard, the Swedish Home Guard, or the Danish Home Guard. In Taiwan, South Korea, Singapore, Colombia, and Israel, service in the reserves is compulsory for a number of years after one has completed national service.

A military reserve force is different from a reserve formation, sometimes called a military reserve, a group of military personnel or units not committed to a battle by their commander so that they are available to address unforeseen situations, bolster defences, or exploit opportunities.

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