War, as defined by the OED, is a continuous process of trying to bring one’s will and that of others into accord; the use of diplomacy, economic pressure (including through multi-national corporations), information operations, social influence and education, and, when necessary, military force. It also includes non-declared and unofficial wars such as guerilla uprisings and terrorist acts, and even culturally evolved and ritualised armed conflict that appear to be independent of any controlling body or state.

It has always been recognised that a war’s ebbs and flows, its fluctuating energy levels and the intensity of its pursuit are its characteristic features. This has prompted comparisons to a dual, a boxing match, or a street fight and the implication that the success of any strategy depends on a combination of courage and stoicism with a willingness to contend in spite of all difficulties. It has also been recognised that unforeseen strategic developments can create uncertainty in decision-making and that friction, such as civil-military disagreements, misreading intelligence or misunderstanding between rivals, can produce setbacks and slowdowns.

The concept of a ‘war’ also has significant implications for morality and the behaviour of those engaging in it. Philosophers have debated its role – from those who argue that morality is discarded by the nature of war, to others who try to remind warriors that they must still be sensitive to moral ends and apply a variety of strictures to avoid falling into sin. Psychologically, going to war, and coming back from it, has been viewed as a psychological transition to a different, more warlike persona, with warriors often performing rites and rituals that symbolise their movement into or out of this ‘state of war’.

Finally, Malthusian theories have long seen rising populations and scarcity of resources as a cause of violent conflict, while others have sought to address resource allocation and distribution using global governance structures such as the Politeia or the Westphalian state system, or by utilising non-state actors.

In a world that increasingly has been reshaped by new technology, the traditional definition of War can no longer be used to distinguish it from other forms of violence. Nevertheless, this working definition allows for a wider range of analysis, including an examination of the way in which nation-states and non-state actors engage with their neighbours and the global community to impose their wills; utilising all means available to them, including diplomatic relations, economic pressure (including through trade agreements, restrictions and embargoes), information operations, social influence and education, as well as – of course – military force when necessary.