International Security
Lecture Notes
WEEK TWO: WHAT IS WAR AND THE CONTINUED RELEVANCE OF CLAUSEWITZ?
Hedley-Bull is a founder of the English school of realism: ‘war is between political units, not
individuals’.
Clausewitz is the typical ‘philosopher of war’ - and often considered still relevant, especially by
realists (particularly the US). He sees war as a rational instrument of policy. Colin Gray (advisor to
UK and US governments, including Ronald Reagan) is a leading proponent of Clausewitz’s views,
seeing his works as still relevant. The nature of War is unchanging and not a construction.
Clausewtiz’s theories are still studied in the professional military today.
On War - the nature of war is permanent and unchanging; the character of war is transformative (i.e.
wars have the capacity to change societies) but these views were developed in the specific context
of the Napoleonic wars, which are also seen as the beginning of modern warfare. Ancient warfare is
seen as involving small forces, being limited, using proportionally less resources and being more
local. In contrast, modern warfare (Napoleonic wars onwards) is characterised by social
transformation, centralised bureaucracy, nationalism, communications, information, transport,
industrialisation, mass participation, state-led operations, mass conscription and modern weaponry.
Also, the objectives of modern warfare are more absolute and the entire population is increasingly
seen as a legitimate target (Sheehan).
On War - Concepts
• Trinity of War - elements of the trinity have to be aligned
• Primary: Rationality, chance/uncertainty and passion/irrationality
• Secondary: Government, people and military
• Example - the Vietnam War. The US won every major battle but still lost the war. This
is explain via Clausewitz through the gap between the military and society.
• War as an instrument of policy - must be calculated and rational; with operational
objectives in addition to political purpose. Vietnam failed ‘because of the lack of such clear
objectives, leading to public disaffection’. This is contested and is evidently not fully
explanatory; what policy is war an instrument of?
• Limited vs unlimited - control the enemy, or destroy the enemy. Gives rise to a conflict
between military (limited, pragmatic) and political (absolute) objectives. But is
Clausewitz’s description an abstracted ‘ideal type’ or does Clausewitz advocate total war?
He emphasises strength of defence over offence.
• Friction - what distinguishes real war from war in theory. Not all variables can be
controlled: even the simplest theories can be made impossibly difficult by real-world
conditions.
• Chance - most of war’s variables are wrapped in uncertainty. Guesswork and luck play a
significant part.
• Fog of War - recurrent inaccuracies of intelligence and an inability to understand the
enemy and even one’s own forces. Also includes the inevitable clouding of judgement in the
field.
Lecture Notes
WEEK TWO: WHAT IS WAR AND THE CONTINUED RELEVANCE OF CLAUSEWITZ?
Hedley-Bull is a founder of the English school of realism: ‘war is between political units, not
individuals’.
Clausewitz is the typical ‘philosopher of war’ - and often considered still relevant, especially by
realists (particularly the US). He sees war as a rational instrument of policy. Colin Gray (advisor to
UK and US governments, including Ronald Reagan) is a leading proponent of Clausewitz’s views,
seeing his works as still relevant. The nature of War is unchanging and not a construction.
Clausewtiz’s theories are still studied in the professional military today.
On War - the nature of war is permanent and unchanging; the character of war is transformative (i.e.
wars have the capacity to change societies) but these views were developed in the specific context
of the Napoleonic wars, which are also seen as the beginning of modern warfare. Ancient warfare is
seen as involving small forces, being limited, using proportionally less resources and being more
local. In contrast, modern warfare (Napoleonic wars onwards) is characterised by social
transformation, centralised bureaucracy, nationalism, communications, information, transport,
industrialisation, mass participation, state-led operations, mass conscription and modern weaponry.
Also, the objectives of modern warfare are more absolute and the entire population is increasingly
seen as a legitimate target (Sheehan).
On War - Concepts
• Trinity of War - elements of the trinity have to be aligned
• Primary: Rationality, chance/uncertainty and passion/irrationality
• Secondary: Government, people and military
• Example - the Vietnam War. The US won every major battle but still lost the war. This
is explain via Clausewitz through the gap between the military and society.
• War as an instrument of policy - must be calculated and rational; with operational
objectives in addition to political purpose. Vietnam failed ‘because of the lack of such clear
objectives, leading to public disaffection’. This is contested and is evidently not fully
explanatory; what policy is war an instrument of?
• Limited vs unlimited - control the enemy, or destroy the enemy. Gives rise to a conflict
between military (limited, pragmatic) and political (absolute) objectives. But is
Clausewitz’s description an abstracted ‘ideal type’ or does Clausewitz advocate total war?
He emphasises strength of defence over offence.
• Friction - what distinguishes real war from war in theory. Not all variables can be
controlled: even the simplest theories can be made impossibly difficult by real-world
conditions.
• Chance - most of war’s variables are wrapped in uncertainty. Guesswork and luck play a
significant part.
• Fog of War - recurrent inaccuracies of intelligence and an inability to understand the
enemy and even one’s own forces. Also includes the inevitable clouding of judgement in the
field.
