Gotcha... It makes sense. Three countries, three sects. Although I’m sure the fights will be over the lines drawn and important cities, shrines, temples, oil fields, etc. Not that simple.
Somewhere way back when we discussed the oil fields, the Kurds having natural access to some, and the Shi’ites to others. That leaves the sunnis having to get theirs via power, which is what old Saddam Hussein did.
It is also a focus of the ISIS leadership, getting theirs the same way as did Saddam.