Everyone wonders why the U.S. military command announced outlines of the plan to retake the city of Mosul from Islamic State control. There is surface clarity but there must be more underneath. The battle plan itself is simple: overwhelming force, with 30-40,000 coalition troops, Iraqi Arab/Kurdish with some Iranian participation and American air and Special Forces support, against 1-2,000 hopelessly outnumbered Islamic State fighters inside the city that can’t hope for much help from IS outside.

But informing the enemy of what coalition forces are going to do strikes us all as either incomprehensible or ominous or both. Critics everywhere, from Senators John McCain and Lindsey Graham to military commentators in the media as well as the average news-conscious citizen wonder what’s really going on. The mystery surrounding the February 20 press conference by a high Central Command officer was deepened and more suspicions raised by weird comments from the White House and the new Secretary of Defense to the effect that they hadn’t known about the briefing and military commanders ‘have some leeway’ in public communications. No one can believe this version of events. No military commander in a war situation would dare operate this way without the highest civilian approval. The weirdest thing was that the Obama people should have thought this might be convincing. A less disdainful view is that they knew it wouldn’t be and this was part of the subterfuge.

The impending battle for control of Mosul is without doubt crucial. Mosul is not only Iraq’s second largest city it’s a mixed urban population, majority Arab in the western parts but with a large Kurdish minority mainly in the east, close geographically to Kurdish Iraq’s capital of Irbil. It represents Islamic State’s largest urban victory, its government there the most developed example of what the “caliphate” would look like on the ground. Most important, taking back Mosul (presumably after the more imminent battle for Tikrit) would make it clear that Islamic State’s territorial expansion in Iraq has been stopped and that, as most informed analysts now agree, IS will be destroyed as a coherent military force in Iraq even if it is able to hang on longer in Syria and even if local terrorist cells survive for some time. In the logic of IS’s strategy of “remain and expand” the caliphate territory, if it’s not expanding it loses plausibility, if it’s not winning it loses credibility. As a matter of common sense, ultimately Islamic State cannot hope to defeat the coalition of enemies it has created for itself. (In my own view, I remain convinced that eliminating Abu Bakr al-Baghdadi, so-called caliph and charismatic symbol of the rise of Islamic State, would impact the whole operation, starting a collapse from within in conjunction with attacking it from the outside.)

Altogether, the stakes in the battle for Mosul are high and many lives hang in the balance—not only those of soldiers but also the civilian population of the city. Two reasons were given for CENTCOM’s description of the battle line: a) psychological warfare against Islamic State fighters to demoralize them and encourage escape, b) stoking up the Iraqi military’s fighting spirit, which, after the humiliating rout when IS first attacked Mosul, is no mean task.

As to the first, we know from past experience how IS fighters will react. They aren’t afraid, won’t try to escape or quit the fight. They know they will die and are even more determined knowing the odds against them. There may be significant casualties among coalition forces. But there is worse, concerning the city and its population. IS will surely set booby-traps to bloody the conquerors but they will first blow up as much of the city as they can, in particular mosques and other religious and public buildings. Many civilians will die. There is even worse yet: as coalition military forces close in, IS fighters are likely to start massacring civilians—perhaps children and women first—in gruesome, public display to put coalition commanders and political leaders before horrible choices. Thousands in Mosul could die horrible deaths if the attack continues but what happens in the contrary case? Surely coalition leaders have thought of this and have an undisclosed plan to decimate the IS fighters in a surprise attack. But surely the central Islamic State’s leadership knows this as well. What then?