Military doctrine

In general, there are four levels of abstraction of military doctrine, the highest level not limited to military means but including all national ways to affect behavior. While terms such as strategy go back to antiquity, the modern usage of these levels starts from Carl von Clausewitz's definition of strategy, with variations on how it is translated from the German, as "the extension of national politics by military means". In modern international usage, additional refinements are needed to deal with non-state actors, sometimes more in combat terms but also in lower-intensity efforts, including peacekeeping, peace enforcement, and nation building. There are also military doctrines, typically for national or multinational organizations, that address the various levels in specific contexts, such as insurgency or air warfare planning.

For centuries, there was, at best, a distinction between strategy and tactics. They used Clausewitz's definition of strategy to define the objectives to start a conflict, and a generic discussion of tactics as how the battles would be fought. Battles, of course, differ in the type of units and rules of engagement, for which there are doctrines. A doctrine for a naval blockade will be very different from a doctrine for light infantry in high-altitude mountain warfare.

In World War II, strategy was at the level of theaters of operations, operational art was at the level of ground units from army group to corps, and naval units at the fleet level; tactics were from division to fire team. The current trend, however, is for militaries with advanced technology to use smaller units at the various levels.

There are levels of abstraction above and below strategy, and the definition of strategy itself has evolved. The main levels are:

Level	Objectives	Types of units involved
Grand strategy	Deciding the full range of national policy toward other actors	Military as a whole, diplomacy, international economic policy, psychological operations, international law enforcement
Strategy	Determining the composition of the military and its deployment; high-level regional objectives in war	Geographic theaters of operations, field army and larger units on land, special operations forces under high-level command, long-range aviation and missiles, sea control and major naval operations
Operational art	Preparing for battle within a geographic or other large scope, and creating the opportunities to engage in battle on favorable terms	Ground troops traditionally at corps size (i.e., 25,000 to 75,000 conventional soldiers), but in highly technological militaries, down to brigade equivalent. Air forces directed as a theater or campaign resource.
Tactics	How battles are fought once begun, or the methods and objectives of quick strikes	Ground troops from fire team (3-5 soldiers) to division (up to 25,000 soldiers)

Grand strategy

Grand strategy includes, but is not limited to, military means, but also diplomacy, economic measures, covert operations, law enforcement, intelligence collection and analysis, psychological operations, etc.

Strategy

Strategy is still considered associated with using military means to influence behavior of other actors, but the term "grand strategy" goes beyond military means as a way to implement politics (or policy).

In contrast, [military] strategy is the highest level of how to structure and deploy a nation's military forces. It must first deal with the strength, composition, and capabilities of those forces, and then decide on a command structure, which is often based on geographic areas of operations, and often domestic or military politics. For example, a basic Allied strategic decision in the Second World War was to divide operations into European, Pacific, and Mediterranean, but, in the Pacific, it was necessary to divide into Southwest Pacific and Pacific Ocean areas. The necessity came from the need to manage the notable ego and skills of Douglas MacArthur.

Units that can independently strike deep in the enemy rear areas can be considered strategic. The most obvious example are long-range bombers and guided missiles, but special operations forces can carry out strategic missions, and either exfiltrate, or stay behind and raise guerilla forces.

The generations of warfare described by these authors are:

First generation warfare

The first minimally industrialized warfare involved rigidly linear troop movements (e.g., line and column), principally direct fire muskets and small cannons. tactics of line and column; which developed in the age of the smoothbore musket. Napoleon introduced some of its concepts, including the division as an early form of combined arms operations, synchronization with the first portable and accurate watches, and the beginnings of decentralization to the level of corps.

Second generation warfare

This was a gradual transition in movement, as artillery and repeating rifles greatly increased the power of the defense. Technology became important in support (e.g., railroads) and communications (e.g., telegraph).

It is difficult to put an exact start on this period, except it is fairly clear that first-generation methods became obviously ineffective at the Battle of Gettysburg. Admittedly, some forces were still learning about the even greater power of the defense in 1914.

Third generation warfare

Usually considered to have started with non-linear movement, by combined arms forces, and attacks in the enemy's rear by Strategic strike|air or special operations forces, the most common start of this phase is associated with German blitzkrieg operations in 1939. Command was increasingly decentralized.

There were earlier hints of breakthrough operations, such as German use of chemical weapons at the Second Battle of Ypres in 1915, the U.S. Army (Union) army to use large explosives with penetration Battle of the Crater in 1864, or British use of massed tanks at the Battle of Cambrai in 1917. All these potential breakthrough operations failed due to failures of communications, understanding of weapons capability, and unimaginative commanders.

Fourth generation warfare

Continuing the nonlinear trend of third generation warfare, this is characterized by extreme decentralization enabled by advanced electronics, special operations forces and non-national actors including revolutionary warfare, and continuous operations. In very different ways, Mao's revolutionary warfare, airmobile operations in Vietnam, and the first network-centric warfare in the Gulf War are all different fourth generation models. Some suggest that the extensive networking among "sensors and shooters", with much improved situational awareness, coupled with the use of precision-guided munitions, may be a fifth generation.

Operational art

Operational art is a relatively new term, between tactics and strategy. If strategy defines one's areas of operations, operational art defines the priorities and campaigns within the various areas. A master of operational art sets conditions such that battles happen at the places, times, and other circumstances that give maximum advantage to one's side. The term "preparation of the battleground", or, in more recent jargon, "preparation of the battlespace", applies here.

Units that are highly mobile within part of a theater, such as air assault troops, or amphibious forces maneuvering at sea, are key ways of selecting the place and conditions of battle, a basic characteristic of the operational level.

Tactics

Tactics deal with how those battles are fought. Unfortunately, the term deals with levels of fighting with organizations ranging from divisions of 25,000 soldiers down to fire teams of 3-5 soldiers.