What the Mosul Study Group Missed - Modern War Institute

"More importantly, Mosul demonstrates that how an army wants to fight is not nearly as important as how an army will have to fight. While doctrine describes how a force wants to fight, many factors—from policy and national caveats to terrain and the enemy’s location—dictate how force will have to fight. With positional battles of attrition on the rise, the US Army must understand that phenomenon and be prepared to survive, fight, and win under such conditions. Therefore, as we look to the future, we should expect to see a rise in the urban defense, characterized by a positional contest of attrition in which victory is not guaranteed simply by having the best-trained soldiers or most high-tech equipment, but by being most able to muster the resources and resolve to weather the attritional slog.

The discussion of decisive battles is not complete without a mention of squandering victory. The effects of a decisive battle can be squandered if not followed by actions that preserve its military and political consequence. In the case of Iraq, for example, the Islamic State is slowly creeping back into previous strongholds—the result of insufficient and ineffective constabulary forces, inadequate reconstruction effort, and misbalanced representation of various factions in the government."