Originally Posted by
2Bad
They aren't forced to do it because there is nothing that forces you to join a fight you aren't part of. As I've said, I understand why the regime would be concerned about it. I am however also saying that the problems they will inevitably create for themselves by an invasion are liable to be far worse than simply waiting to see how this plays out. Spending blood and treasure (that Iran doesn't have to spare) fighting a nightmarish guerilla war doesn't do well for your internal stability. Nor is grabbing land from your co-religionist neighbor a great long-term move for that relationship. What land would they even take? South Kurdistan itself? That'd be essentially giving up on Baghdad ever being a friendly relation of any sort, and it's effectively creating the unified South-East front you're afraid of in the first place. Hell, some in Rojava might seek turn their eye East, and of course you always have Northerners jumping the border to join the fights in Rojava and the South.
It's essentially starting the war now because you're afraid it might start later. Preemptive action has its place, true, but this just seems like a bad gamble.
e: as for the west, well, I don't know if you've noticed, but the West DOESN'T care about pissing off everyone in the region. Just Turkey (which hey, would certainly be mad but acts up all the time anyway) and the Gulf states really (who would be absolutely thrilled to see Iran and the Baghdad government kicked around... and act up all the time anyway).