“Even war has rules,” said Doctors Without Borders head Dr. Joanne Liu as part of her response to the devastating U.S. bombing of the organization’s hospital in Kunduz, Afghanistan earlier this October. After a series of different explanations and excuses — four separate accounts of the incident over the first four days, by The Guardian’s count — the United States still hasn’t provided a concrete explanation as to why and how the hospital was targeted, killing 22 doctors and patients. The attack was the worst on any Doctors Without Borders hospital in its 44 years of operating. But it wasn’t all that different from other recent U.S. attacks on civilian infrastructure. Since as far back as 1991, the U.S. has been “accidentally” blowing up medical and humanitarian facilities in a range of places, resulting in high civilian casualties and other “collateral damage.”