The Duke of Wellington famously once said: ‘All the business of war, indeed all the business of life, is to endeavour to find out what you don’t know from what you do: that is what is called “guessing what’s on the other side of the hill”.’ Wellington was not the sort of commander who was comfortable with simply guessing what was on ‘the other side of the hill’, but he did understand that he might have to make life-and-death decisions, with serious political and military consequences, on incomplete knowledge. In order to reduce the gap between ignorance and certainty he invested a great deal of time, effort, and even money, in trying to turn a ‘guess’ into something much more tangible, and therefore militarily useful.

All commanders, before and since, have attempted to achieve the same. Those that succeeded in creating an information-based decision-making process have had military success, those that have neglected this vital aspect of warfare, or have been thwarted in trying to gain greater degrees of certainty, have often been defeated. On such success or failure, empires have risen or fallen. Much of any success, in any walk of life, starts with the acquisition of knowledge, defined as ‘facts, information, skills, awareness and familiarity acquired through experience and, or, education’. This capability to absorb facts and experience and to draw lessons from them, mark out the higher animals, most obviously man. Increased experience – for much of history dependent on the capacity of an individual or community to survive – breeds confidence and, with it, the familiarity that influences behaviour.

In the military sphere we speak of war’s ‘enduring nature’, which is as a brutal, volatile, dynamic human activity, with uncertain outcomes. Given that war, a large-scale, organised phenomenon, distinctly different from simply ‘fighting’, only takes place periodically, this knowledge of what war can be like is easily neglected, forgotten, and often lost in peacetime. The great Athenian historian, Thucydides, opined that, while fighting and conflict were endemic to the human condition, the three primary causes of organised war between formed polities were honour, fear and self-interest, and his proposition has proved to be remarkably resilient.

By the 19th century, given the historical development of empires, states and nations, the Prussian general and military theorist, Carl von Clausewitz encapsulated the harnessing of war to a higher, or more structured, purpose, in his great maxim: ‘War is not merely an act of policy, but a true political instrument, constituting a continuation of political activity by other means.’ Western military academies also contend, however, that while the nature of war is enduring, the character of war does change, and that experience, technological advance, economic growth and societal development all lead to wars, as an extension of political activity, being fought in different ways, at different times and in different circumstances.

Therefore, in this balance between the nature and character of war, British soldiers fighting in Iraq in the early 21st century would have no difficulty empathising with legionaries engaged in Rome’s imperial adventures in the Euphrates River valley in the 3rd century, albeit the strategic context may have been radically changed, and the weaponry appeared alien. That said, both sets of soldiers, sweating in the desert sun, encased in helmets and breastplates, shouldering heavy packs, and conscious of daily hardship and threat would have felt that ‘brotherhood of arms’ that transcends geography and history. They would both have applauded Robert Gates, a US Secretary of Defense, who said that military and civilian leaders alike should ‘look askance at notions of future conflict… where adversaries can be cowed, shocked or awed into submission, instead of being tracked down, hilltop by hilltop, house by house, block by bloody block.’ Or General ‘Vinegar Joe’ Stilwell who warned: ‘No matter how a war starts, it ends in mud.’

Roman legionary and British ‘Tommy’ would both have relied upon their own knowledge, and that of their commanders, for tactical success in fighting, but would also have sought, and benefited from ‘intelligence’ to prosecute the overall campaign successfully. In this context, intelligence constitutes those facts that are accurate, timely, specific, organised for a purpose, and presented in context. This is the intelligence that helps commanders know or assess, rather than guess, what is on the other side of the hill. It decreases uncertainty and permits purposeful activity, in time and space, in order to achieve battlefield advantage. Needless to say, any opposing commander worth his salt is attempting to achieve the same results, and both commanders have a strong vested interest in thwarting the other’s efforts: by stopping the enemy knowing what is on your side of the hill.

To this end, serious armed forces invest enormous resources in intelligence, in its widest sense and at all levels, because, when the stakes are so high, the investment is deemed to be worthwhile. This investment has grown exponentially in recent decades, as technology has offered ever newer ways of determining what is on the other side of the hill. To intelligence staff, who relied for centuries on those long-standing elements of human intelligence – knowledge, experience, traitors, collaborators and spies – we have now progressively added signals intelligence, image intelligence and electronic intelligence. The huge, exponential advances in technology clearly have made the intelligence ‘battle’ even more complex and sophisticated. We are still trying to guess what is on the other side of the hill, we just have more tools to help us do so.

The other, commonly understood meaning of the word intelligence is that of general, cognitive problem-solving skills. To say that someone is highly intelligent is a mark of approbation and distinction, and is a quality to be found in the best leaders and commanders in all fields of human endeavour. What all leaders are consistently attempting to do is to apply intelligence, as a cognitive skill, to ‘intelligence’ – that timely and accurate, contextualised knowledge which drives informed decision-making. As this process has become more complicated and complex, so the development of military intelligence as both a branch of the armed forces and a sophisticated military process in itself, has grown. It has become a vital, resource-intensive, military discipline that drives information collection, and then delivers considered, informed analysis, in order to provide the guidance and direction that assists commanders in their decision-making. It is intelligence that drives what is often referred to as the ‘decision-action cycle’, whereby information is turned into situational awareness that in turn allows a commander to choose a course of action from several possible options, and to give clear orders for his forces to execute.

There is no magic about this, and all armies try to go through the same cycle, but an experienced, intelligent commander, served by a competent staff, who have all trained together, can make this into a very well-oiled process that, at its best, rapidly gets inside an opponent’s own decision-action cycle. In doing so, it increasingly makes the enemy’s responses to your own movement and manoeuvre incoherent or irrelevant. Allied to this are good communications that allow the rapid passage of orders, preferably without those messages being intercepted or read by an enemy. This was at the heart of the German blitzkrieg success in the opening years of the Second World War. This process was later captured in the mnemonic OODA: Observe, Orientate, Decide, Act. This was a way of helping people visualise a cycle of cognition and action that was developed in the American air combat school in the 1950s by a Lieutenant Colonel Boyd, in order to restore US supremacy in aerial dog-fights over Korea. While the ‘OODA Loop’ was initially aimed at fighter pilots in single-combat, its generic relevance at much higher levels of war and conflict was quickly understood.

Adopted and taught across most Western militaries, the OODA Loop was deployed by Special Forces in the conflicts of Iraq and Afghanistan and developed to serve another sophisticated intelligence-driven cycle known as F3E: Find, Fix, Finish, Exploit. Given Clausewitz’s exhortation to always acknowledge that war is a political activity, the importance of intelligence, in terms of both information and analysis, at every level, and through every phase of a war, is evident and paramount. Given the hard experience of recent conflicts, it is clear that guessing what is on the other side of the hill is as vital in informing the political decision to use war as a policy tool, and in bringing the campaign to a successful and positive political conclusion, as it is to actually fighting the conflict itself.

Clausewitz, in another of his timeless observations, noted: ‘The first, the supreme, the most far-reaching act of judgement that the political statesman, and the military commander, have to make is to establish the kind of war on which they are embarking; neither mistaking it for, nor trying to turn it into, something that is alien to its nature.’ The US General, David Petraeus, who commanded Coalition forces in both Iraq and Afghanistan, often used to say that military commanders needed to ask their political leaders ‘Tell me how this ends?’ in order to ensure that all military activity, not simply the fighting, is conducted in a manner that serves the political objectives.

This political-military interface, and sometimes tension, therefore drives a requirement for strategic intelligence, analysed and assessed by both the military and political leadership, which should profoundly influence any decision to go to war, or not. This will be driven by an assessment of the geopolitical situation in which a state finds itself. This will include treaties, allies and obligations, lack of resources or the appetite for more, relative economic and military strengths, ambitions, inspirations and grievances, and issues of government, governance and the historical interplay of personalities. Much will depend on whether a state plans or fears aggression, is prepared for war, or has the capacity, depth and willingness to be invaded and to strike back.

Whether a state plans or fears aggression, the military commanders need to take the political decision, or assessment, and prepare their own operational intelligence, primarily focused on the range of military activities anticipated in an offensive or defensive campaign. This will be needed prior to the outbreak of any hostilities, and throughout a campaign once hostilities commence. This requires detailed understanding of terrain for manoeuvre – of rivers, mountains, coastlines, urban centres, airbases and ports – and of the relative strengths and capabilities of one’s own forces, and those of allies and potential opponents, and knowledge of civilian attitudes and potential response.

In large-scale warfare this operational intelligence is crucial for the effective correlation of forces, in the air, land and maritime domains, in both time and space. It helps determine the ‘design for battle’. The effective use of operational intelligence, and the operational-level excellence that can flow from it, was well demonstrated by the German army’s actions against the formations of the Soviet Union in the Second World War. The Coalition forces at the outset of the Gulf War in 1991, and the invasion of Iraq in 2003, also demonstrated an outstanding operational capability based on good operational intelligence. However, like those early German military successes in Russia, the disconnect from a well thought-through, achievable political strategy and end-state, meant that all of this activity could not rescue a military campaign from eventual political failure, as judged by Clausewitz. The failures of strategic intelligence, let alone the motivations of the protagonists, severely undermined the efficacy of any local military success or individual bravery.

The third level of intelligence is that of tactical intelligence which, in time frame and scale, is more directly related to the tactical activities of the formations on the battlefield. This level of intelligence is often literally related to the requirement for a commander or soldier to try and guess what is on the other side of the hill, and to take whatever information they can get in order to achieve their tactical objectives. Sun Tzu, the great Chinese military philosopher and thinker, was attributed as saying: ‘Strategy without tactics is the slowest path to victory. Tactics without strategy is the drumbeat before defeat.’ Both strategy and tactics need sound intelligence, and intelligent assessment, and history is littered with examples of the failures of one or the other, or both. History also has many examples where strategy and tactics have been well-informed by intelligence and, as a result, have been effectively and successfully harnessed to the achievement of sustainable political outcomes.

War is a political act, and statesmen, politicians, and military commanders all require knowledge and intelligence and, with those, the capacity and means to understand, analyse and assess both. Judgement, and even wisdom, both political and military, is vital in this equation, given the strategic consequences of failure. Intelligence reduces uncertainty, and it allows a better and more objective assessment of risk, benefit and cost. However, it is prone to information overload, to ‘heroic but false assumptions’, to poor judgement, to reinforcing prejudices or to what is known as ‘paralysis by analysis’. This is where the desire to maximise certainty delays critical decision-making, and the ‘best’ intelligence becomes the enemy of ‘good enough’ intelligence. All of which is to say that intelligence is an absolutely vital part of leadership and command, at every level, and that its management, as a product and as an asset, is critical in all phases of war, and peace.

When I was the Coalition’s Deputy Commander in Baghdad, back in 2007, I worked for General David Petraeus. On the wall in his office he had hanging a classic picture of the Wild West in which cowboys were racing alongside charging cattle that had clearly been panicked into a state of frenzy by a lightning storm. It was titled Stampede, and General Petraeus likened the situation in Iraq at that stage as akin to a chaotic stampede, with the Coalition forces attempting to corral the conflicting elements bringing chaos to Iraq. ‘What I need around me’, he said, ‘are people who are comfortable in a stampede.’ Good intelligence, and the capacity to use it properly, is an important capability in helping to deliver that sense of comfort.

This essay originally appeared in ‘Knowledge and Information: Perspectives from the Engelsberg Seminar’, Bokförlaget Stolpe, in collaboration with Axel and Margaret Ax:son Johnson Foundation, 2018.