Grand strategy
Definition: There is no universally accepted definition of grand strategy. One common definition is that grand strategy is a state's strategy of how means (military and nonmilitary) can be used to advance and achieve national interests in the long-term.
Grand strategy expands on the traditional idea of strategy in three ways:

expanding strategy beyond military means to include diplomatic, financial, economic, informational, etc. means
examining internal in addition to external forces – taking into account both the various instruments of power and the internal policies necessary for their implementation (conscription, for example)
including consideration of periods of peacetime in addition to wartime
Thinkers differ as to whether grand strategy should serve to promote peace (as emphasized by B. H. Liddell Hart) or advance the security of a state (as emphasized by Barry Posen).

British military historian B. H. Liddell Hart played an influential role in popularizing the concept of grand strategy in the mid-20th century. Subsequent definitions tend to build on his. He defines grand strategy as follows:
[T]he role of grand strategy – higher strategy – is to co-ordinate and direct all the resources of a nation, or band of nations, towards the attainment of the political object of the war – the goal defined by fundamental policy.
Grand strategy should both calculate and develop the economic resources and man-power of nations in order to sustain the fighting services. Also the moral resources – for to foster the people's willing spirit is often as important as to possess the more concrete forms of power. Grand strategy, too, should regulate the distribution of power between the several services, and between the services and industry. Moreover, fighting power is but one of the instruments of grand strategy – which should take account of and apply the power of financial pressure, and, not least of ethical pressure, to weaken the opponent's will. ...
Furthermore, while the horizons of strategy is bounded by the war, grand strategy looks beyond the war to the subsequent peace. It should not only combine the various instruments, but so regulate their use as to avoid damage to the future state of peace – for its security and prosperity.

History: In antiquity, the Greek word "strategy" referred to the skills of a general. By the sixth century, Byzantines distinguished between "strategy" (the means by which a general defends the homeland and defeats the enemy) and "tactics" (the science of organizing armies). Byzantine Emperor Leo VI distinguished between the two terms in his work Taktika.
Prior to the French Revolution, most thinkers wrote on military science rather than grand strategy. The term grand strategy first emerged in France in the 19th century. Jacques Antoine Hippolyte, Comte de Guibert, wrote an influential work, General Essay on Tactics, that distinguished between "tactics" and "grand tactics" (which scholars today would refer to as grand strategy). Emperor Leo's Taktika was shortly thereafter translated into French and German, leading most thinkers to distinguish between tactics and strategy.
Carl von Clausewitz proposed in an influential work that politics and war were intrinsically linked. Clausewitz defined strategy as "the use of engagements for the object of the war". Antoine-Henri Jomini argued that because of the intrinsically political nature of war that different types of wars (e.g. offensive wars, defensive wars, wars of expediency, wars with/without allies, wars of intervention, wars of conquest, wars of opinion, national wars, civil wars) had to be waged differently, thus creating the need for a grand strategy. Some contemporaries of Clausewitz and Jomini disputed the links between politics and war, arguing that politics ceases to be important once war has begun.
Narrow definitions, similar to those of Clausewitz, were commonplace during the 19th century. Towards the end of the 19th century and into the early 20th century (in particular with B. H. Liddell Hart's writings), some writers expanded the definition of strategy to refer to the distribution and application of military means to achieve policy objectives. For these thinkers, grand strategy was not only different from the operational strategy of winning a particular battle, but it also encompassed both peacetime and wartime policies. For them, grand strategy should operate for decades (or longer) and should not cease at war's end or begin at war's start.
In the 20th century, some thinkers argued that all manners of actions (political, economic, military, cultural) counted as grand strategy in an era of total warfare. However, most definitions saw a division of labor between the actions of political leaders and those of the executing military.
According to Helmuth von Moltke, the initial task of strategy was to serve politics and the subsequent task was to prepare the means to wage war. Moltke however warned that plans may not survive an encounter with the enemy. Other thinkers challenged Clausewitz's idea that politics could set the aims of war, as the aims of war would change during the war given the success or failure of military operations.These thinkers argued that strategy was a process that required adaptation to changing circumstances.
Scholarship on grand strategy experienced a resurgence in the late 1960s and 1970s. Bernard Brodie defined strategy as "guide to accomplishing something and doing it efficiently... a theory for action".

Historical examples: According to historian Hal Brands, "all states... do grand strategy, but many of them do not do it particularly well."

Peloponnesian War: One of the earlier writings on grand strategy comes from Thucydides's History of the Peloponnesian War, an account of the war between the Peloponnesian League (led by Sparta) and the Delian League (led by Athens).

Roman Empire: From the era of Hadrian, Roman emperors employed a military strategy of "preclusive security—the establishment of a linear barrier of perimeter defence around the Empire. The Legions were stationed in great fortresses".

These "fortresses" existed along the perimeter of the Empire, often accompanied by actual walls (for example, Hadrian's Wall). Due to the perceived impenetrability of these perimeter defenses, the Emperors kept no central reserve army. The Roman system of roads allowed for soldiers to move from one frontier to another (for the purpose of reinforcements during a siege) with relative ease. These roads also allowed for a logistical advantage for Rome over her enemies, as supplies could be moved just as easily across the Roman road system as soldiers. This way, if the legions could not win a battle through military combat skill or superior numbers, they could simply outlast the invaders, who, as historian E.A. Thompson wrote, "Did not think in terms of millions of bushels of wheat."

The emperor Constantine moved the legions from the frontiers to one consolidated roving army as a way to save money and to protect wealthier citizens within the cities. However, this grand strategy, according to some ancient sources, had costly effects on the Roman empire by weakening its frontier defenses and allowing it to be susceptible to outside armies coming in. Also, people who lived near the Roman frontiers would begin to look to the barbarians for protection after the Roman armies departed.  This argument is considered to have originated in the writings of Eunapius As stated by the 5th century AD historian Zosimus: Constantine abolished this frontier security by removing the greater part of the soldiery from the frontiers to cities that needed no auxiliary forces. He thus deprived of help the people who were harassed by the barbarians and burdened tranquil cities with the pest of the military, so that several straightway were deserted. Moreover, he softened the soldiers who treated themselves to shows and luxuries. Indeed, to speak plainly, he personally planted the first seeds of our present devastated state of affairs – Zosimus
This charge by Zosimus is considered to be a gross exaggeration and inaccurate assessment of the situations in the fourth century under Constantine by many modern historians.  B.H. Warmington, for instance, argues that the statement by Zosimus is "[an] oversimplification," reminding us that "the charge of exposure of the frontier regions is at best anachronistic and probably reflects Zosimus' prejudices against Constantine; the corruption of the soldiers who lived in the cities was a literary commonplace."

World War II: An example of modern grand strategy is the decision of the Allies in World War II to concentrate on the defeat of Germany first. The decision, a joint agreement made after the attack on Pearl Harbor (1941) had drawn the US into the war, was a sensible one in that Germany was the most powerful member of the Axis, and directly threatened the existence of the United Kingdom and the Soviet Union. Conversely, while Japan's conquests garnered considerable public attention, they were mostly in colonial areas deemed less essential by planners and policy-makers. The specifics of Allied military strategy in the Pacific War were therefore shaped by the lesser resources made available to the theatre commanders.

Cold War: The US and the UK used a policy of containment as part of their grand strategy during the Cold War.