If the dam breaks, ISIS will be judged responsible for more deaths than the atomic bombs dropped on Hiroshima and Nagasaki. Maintenance on the dam almost entirely stopped when ISIS took over, and the grouting machines required for maintaining it were looted. And the dead will be Sunni Muslims--their own "citizens", those who didn't flee when ISIS took control of Mosul.

It will be the lasting legacy of ISIS.

Surely this is a factor in the timing of the US-led effort currently underway to retake Mosul from ISIS, backed by the Iraqi Army.