08 Jan 15. There is no question that the United States should do what it can to minimize civilian casualties. At the same time, war is war, and the United States is fighting an asymmetric war against a movement that does not wear uniforms, may or may not mark its vehicles, and can draw on decades of experience in regional conflicts where irregular forces have used civilians as human shields.

The United States has the most advanced military technology in the world, and its combination of intelligence, surveillance, and reconnaissance capabilities give it a unique ability to combine imagery, signals intelligence, electronic intelligence, and unmanned intelligence for targeting purposes. Its unmanned aerial vehicles (UAVs) give it the capability to watch potential targets in real time, and its unmanned combat aerial vehicles (UCAVs) give it the capability to both watch potential targets and strike them in real time.

But, and this is a critical but in modern warfare, the United States and its allies are fighting enemies that are doing everything they can to use civilians as cover, have learned from Afghanistan and previous fighting in Iraq how to minimize their exposure to U.S. intelligence assets, and are more than willing to move along with civilians, co-locate with them, and mimic civilian movement patterns to cover their own activities. The United States is also again fighting a movement in the Islamic State or Daesh which will do everything possible to exaggerate civilian casualties for propaganda purposes, claim its own casualties are civilians, and claim its own facilities are civilian facilities.

There is no such thing as perfect war at any time, and this is particularly true in this war – as it has been in the fighting in Afghanistan. Rules of engagement that minimize unnecessary civilian casualties are vital both for humanitarian reasons and to avoid alienating the very people we are trying to help and to persuade to join us in the fight. At the same time, attempting to avoid all civilian casualties will paralyze U.S. ability to use some of its most effective ways of striking enemies like the forces of the Islamic State. For all our technical advantages, there are many times where the intelligence is uncertain, the imagery is unclear, and the time windows for a strike are too short for anything approaching “certainty.”

All of the other military options also mean giving the enemy a near sanctuary in rear areas, encouraging every possible use of human shields, and increasing the vulnerability of U.S. and allied forces. They give the terrorist or insurgent the ability to offset or negate the ability to strike them with minimal U.S. and allied casualties. They also allow groups like the Islamic State to keep pushing the limits to the U.S. and allied use of force by exaggerating civilian losses and claiming their casualties are civilians. Human rights and the laws of war become political and military weapons in the hands of terrorists and extremists that have no practical limits and constraints.

It is also critical to take account of the real mathematics of both war and extremism. The brutal reality of war is that it is the cumulative butcher’s bill that really counts – not the civilians killed or hurt in a given set of strikes. The wrong constraints on the use of airpower, UCAVs, and other forms of precision strikes mean much higher levels of cumulative damage and pain.

This means the total damage to civilians will be far higher over time. Movements like the Islamic State can occupy and terrorize civilian areas for much longer periods. Rear areas become sanctuaries for extremism. The abuse of minorities and any civilians the Islamic State chooses to kill, torture, extort, and imprison is enabled. The quick and decisive use of force becomes more difficult; the length of battles, campaigns, and wars is extended; and the total number of civilians killed, wounded, refugees, internally displaced, and terrorized becomes much higher.

No one likes this kind of math or coping with these realities. They are, however, the realities that shape the war we are fighting. They mean we need to explicitly face the grim trade-off between limiting the use of force and making it effective, and between one cause of civilian casualties and another.

The United States must do what it can to limit civilian losses, but it must do that with the grim realism and objectivity required. Similarly, calls for human rights and limits to the use of force must be equally realistic. Empowering movements like the Islamic State at the expense of effective action against them – raising the total butcher’s bill over time – is scarcely going to be any form of humanitarian success.

Anthony H. Cordesman holds the Arleigh A. Burke Chair in Strategy at the Center for Strategic and International Studies in Washington, D.C.

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