As well as such central pillars of his theory as the trinity, the climate of war and
friction, there is a long list of powerful, or at least intriguing, ideas. Clausewitz intro-
duced the metaphor of the fog of war, referring to the ‘uncertainty of all information’
(p. 140). Modern technology may seem to overwhelm the commander with information,
but more often than not that information will not be of the most useful kind. For example,
the Clausewitzian ‘fog’ is especially prevalent in war waged against irregular enemies.
How well are we doing? When will victory be secured? Is victory possible? These ques-
tions have been posed, and have defied confident answer, in war after war, both regular
and irregular. Despite the wonders of the information revolution, it is no easier to answer
these questions in the twenty-first century than it was a hundred years ago.
Among his many important ideas, true to the intellectual climate in Germany of
his time Clausewitz laid emphasis upon what he called the moral qualities in war. He
stressed the significance of the will and of character as contrasted with sheer intellect.
This is especially relevant as a caveat to countries whose defence establishments have a
preference for technological, at least material, solutions to strategic problems. Also, he
warns against cleverness as a sufficient qualification for high command. Brain power and
robustness (or stability) of character are by no means synonymous.
An idea he advanced which has prompted seemingly endless debate is the notion of
the ‘center of gravity...the hub of all power and movement, on which everything
depends’ (pp. 595–6). This is an idea that, unlike so much else in On War, soldiers find
directly useful. Whether they employ the concept as Clausewitz intended is, of course,
another matter. The hypothesis of the centre of gravity lends itself to over-simple attempts
at real-world application. Clausewitz appears to offer exactly what a military planner,
even a grand strategist, needs. By popular interpretation, every belligerent has a centre
of gravity which, if destroyed, severely damaged, paralysed, captured or credibly threat-
ened – whichever condition is appropriate to its particular character – must mean his
defeat. Despite the many problems with this concept, not least the fact that in wars for
limited objectives one should be careful not to menace the enemy’s centre of gravity, the
idea does have merit. As an aid to strategic historical understanding, the concept has
some value. In World War I, for example, the centre of gravity of the Central Powers was
the German Army on the Western Front; in World War II it was the person of Adolf Hitler.
In order to reach Hitler, though, the Allies first had to defeat the German Army, and most
of that army was deployed on the Eastern Front.
The last of the ideas on the nature of war to be cited from the Clausewitzian canon is
the distinction he draws between the policy logic and the grammar of war (p. 605). With
this distinction he insists that even though warfare must be subordinate to the political
purposes that caused, launched and ultimately direct it, organized violence in any period
has a military integrity of its own. When a policy-maker orders ‘go’, the military machine
must fight in the only ways that it is able, subject, naturally, to interference from the
enemy. What Clausewitz is saying is that although warfare is, and has to be, a political
instrument, it is still warfare and it has a ‘grammar’, a technical and human character
unique to itself and particular to a time and place. Politicians have been known to forget
that. They can believe, fallaciously, that warfare is a precise instrument for the infliction
of surgical-style damage in the interest of political goals. They are wrong. Warfare is a
very blunt instrument, even in an age when the most modern military establishments
pride themselves on their claimed ability to use force in so exact a manner that unwanted
26 War, peace and international relations