This analysis makes constant reference to strategic ideas at two different yet connected
levels. On the higher plane there is a general theory of war and strategy authoritative for
all kinds of warfare, by all character of belligerents, using all manner of weaponry and
tactics, in all historical periods. But this general theory, of which Clausewitz’s On Waris
the exemplar by a country mile and more, does not address the specific concerns of actual
policy-makers and soldiers. That is not a weakness. Had Clausewitz written the best
manual of strategic advice of which he was capable, his work would have been instantly
dated. His advice would have been useful only in the military context of his time. On the
lower plane, in contrast, chapter after chapter of this discussion shows both how well and
how poorly historical players managed to cope with the challenges of revolutionary
changes in the contexts and the character of war. Clausewitz is brilliant and invaluable,
but how does one succeed in land warfare against an entrenched enemy who has no
flanks, which was the situation on the Western Front from 1916 to 191 8? Or, with the
British Army expelled ignominiously from continental Europe in May–June 1940, just
how should, or could, Britain continue to prosecute the war, let alone hope to win? By
and large, in fact near exclusively, the historical strategic questions and answers that
occupy the attention of most of this analysis are not of an elevated philosophical nature;
rather, they are eminently, even desperately, practical.
The historical record shows beyond any reasonable doubt that strategic thinking is vital
to the shaping of strategic behaviour. But the record also shows that that thinking has
been stimulated all but invariably by the pragmatic needs of policy-makers and soldiers
who are more or less baffled by new strategic problems and opportunities. Paul Hirst
asserts that ‘War is driven by ideas about how to use weapons and military systems
almost as much as it is by technical and organizational changes themselves. Ideas are
thus crucial’ (Hirst, 2001: 9). But one should not interpret Hirst’s claim as meaning
anything other than that the development of strategic ideas is driven by the actual
challenges revealed in warfare, or in preparation for it. Strategic ideas do not occupy the
driving seat of strategic history. That place is reserved for politics.
Jomini and Clausewitz
Clausewitz has no plausible rival in his articulation of the nature of war and strategy.
Indeed, his reputation as the most penetrating theorist of war is unchallenged by serious
criticism. However, the actual influence of the Prussian theorist almost certainly has
been a great deal less than it deserved. The reasons are not hard to locate. Clausewitz
aimed to educate the mind, not to advise directly for action. Many of the politicians and
soldiers who have been familiar with Clausewitz’s theory either failed to grasp its key
elements or chose to ‘cherry-pick’ those ideas, lifted out of intellectual context, which
best fitted their preferences. On Waris a work of educational intent, not a practical guide
to behaviour. In Clausewitz’s words (1976: 141), ‘Theory should be study, not doctrine.’
The trouble is that many of the minds that must grapple with strategic challenges are
uneducable. For a leading example, none other than the great Elder Moltke, cited already
as the leading nineteenth-century propellant of Clausewitz’s reputation, held a view of
strategy and of the effective autonomy of military operations which was directly anti-
thetical to the argument in On War. Moltke bequeathed to his successors on the Great
General Staff these deadly nostrums: ‘The demands of strategy grow silent in the face of
Clausewitz and the theory of war 19