Clausewitz considered that “people’s war”, or popular resistance to an invader, is one of several factors that makes defence the stronger form of war. As the enemy advances deeper into another country, his forces become dispersed, his formations become depleted, and his supply lines become stretched. The more spread out the enemy is, the more vulnerable he becomes to guerrilla attacks by “militias and bands of armed civilians”.
During the Napoleonic wars, people’s war was regarded as a new phenomenon; its potency had been demonstrated in Spain and Russia where guerrilla resistance played a significant part in wearing down the French invaders. But chapter 26, which analyzes people’s war, shows that Clausewitz was struggling to come to terms with its potential. It’s clear that he viewed guerrilla activity as auxiliary to the action of the army, perhaps analogous to the light troops who in battle skirmished to the front and on the flanks of heavy infantry formations…
“Militia and bands of armed civilians cannot and should not be employed against the enemy main force – or indeed against any sizeable enemy force. They are not supposed to pulverize the core but to nibble at the shell and around the edges. They are meant to operate in areas just outside the theatre of war – where the invader will not appear in strength – in order to deny him these areas altogether.”
If Clausewitz underestimated the revolutionary potential of people’s war, he correctly grasped its essential nature…
“A general uprising…should be nebulous and elusive; its resistance should never materialize as a concrete body, otherwise the enemy can direct sufficient force at its core, crush it, and take many prisoners….On the other hand, there must be some concentration at certain points: the fog must thicken and form a dark and menacing cloud out of which a bolt of lightning may strike at any time.”
There’s a echo of this in T E Lawrence’s Seven Pillars of Wisdom. Setting out a theory of guerrilla warfare, as applied during the Arab revolt against Ottoman rule of 1917-18, Lawrence described guerrillas as “an influence, an idea, a thing intangible, invulnerable, without front or back, drifting about like a gas….a vapour, blowing where we listed.” Lawrence’s thinking was influenced by Clausewitz, who he described as “intellectually so much the master” of the other great military theorists.
Where the two men differed was that Clausewitz saw guerrilla bands as auxiliary to the conventional army, whereas Lawrence foresaw guerrilla formations cut loose from regular armies and operating as strategic forces in their own right.
Clausewitz, I think, was more right than Lawrence: a guerilla army without either a sanctuary or regular army support ends up getting crushed. (One thinks of the Peninsular War, where as long as Wellington maintained his army in being the French could either concentrate against Wellington only to have the Spanish rise up against them everywhere else, or disperse to put down the guerillas only to have Wellington’s army start picking them off piece by piece.) The Iraq war is an example of the same thing: guerillas can be crushed given sufficient force and patience.