Iraqi officials report that a U.S. airstrike killed nearly 200 civilians in West Mosul in mid-March. The U.S. military acknowledged that it had carried out a mission in the area and is now investigating this strike as well as another in March, said to have killed dozens of civilians near the Syrian city of Raqqah.
When a missile meets its target, chemicals inside the weapon combine, causing gases to expand and exert pressure on the warhead, which shatters outward, turning it into shrapnel behind a blast wave. This wave, faster than the speed of sound, compresses the surrounding air, pulverizes any nearby concrete, plaster, or bone, and creates a vacuum, sucking debris back to the zero point. The chemical interaction also produces heat, causing fire.
Although the ensuing civilian casualties may seem like unstoppable tragedies, they are not. Civilian casualties are not inevitable. They are a choice.
The U.S. military predicts how many people will die in its airstrikes by surveilling and estimating the population within a proposed blast radius. It also sets a limit on the number of innocent people each command is authorized to kill incidentally. This limit, called the Non-Combatant Cutoff Value, or NCV, is perhaps our starkest rule of engagement, and it varies region-by-region for political reasons.
In Afghanistan, civilian casualties caused by U.S. airstrikes are considered a liability in our relationship with that country's government. The NCV for Afghanistan is therefore zero.
In Iraq and Syria, the calculus is different. The Pentagon believes the Islamic State of Iraq and Syria (ISIS) is a greater threat than the Taliban; the Iraqis have been requesting more aggressive support; the fighting is more urban.
Last year in Baghdad, I asked then-U.S. Army spokesman Col. Steve Warren what the NCV was for Iraq. That is: How many innocent Iraqis was his command authorized to kill incidentally in an airstrike?
"There are numbers — we don't put those numbers out," he told me, "and here's why we don't put 'em out: Because if the enemy understand, 'Oh if I have X number of civilians around a thing,' its gonna be harder for [the U.S. to arrack] right? So that's a piece of information that we protect."