Insurgencies are a theory of victory adopted by political movements that acknowledge they can not achieve victory through traditional battle. Insurgents provoke occupying armies to use conventional firepower in ways that alienate the local population, thereby creating a steady supply of new insurgents and presenting the occupier with a protracted conflict it may lack the will to complete. In principle, any war that results in the occupation of another country could potentially lead to an insurgency. But once one starts, conventional military superiority can not eliminate it, for the battle has shifted from a military contest to a contest of competing wills. Because of the asymmetry in relative stakes of the occupied and the occupier in the outcome, the balance of competing wills can often come down in favor of the insurgents.

Any decision for war that envisions the occupation of another country must be informed by this uncertainty, particularly one in which the conventional military balance greatly favors the potential occupier. In such cases, pre-war planning for conventional military victory will not prepare the victor for a postwar occupation with insurgency.

For example, the planning for the Iraq war focused overwhelmingly and successfully on defeating the Iraqi military, taking Baghdad, and deposing the regime. But this force was not optimized for achieving the war’s much more ambitious political-military and grand-strategic objectives, such as the establishment of a new regime and its protection from potential internal challenges should an insurgency emerge.

Thus, ironically, it is the most powerful countries, most prone to fight wars of choice with ambitious grand-strategic objectives against much weaker opponents, that are most vulnerable to the trap of winning battles and losing wars. More than anything else, the United States needs a way of thinking about victory in war under such circumstances. It is a gamble to go to war when one’s grand-strategic objectives are great but one’s willingness to engage in significant mobilization and incur major postwar obligations is limited. This leaves much of the initiative in the hands of one’s opponent. Will he accept military defeat or decide to transform the conflict into a contest of competing wills? Should one prepare for the worst and mobilize for war assuming the latter? Victory In War: Foundations of Modern Military Policy provides much of the history and analysis that would be needed to answer questions such as these but, in the end, does not address them. This is unfortunate because they badly need answering.