You think the Saudis are making their nice white robes a little yellowish brown? They know they are next.
And if they get to Basra, Iran is going to come across the border in a big way. This has been my thoughts on this since the start. They WANT Iran to cross the border. That would be the casus belli.
Someone else who might be getting that sinking feeling is our old friend Muqtada al-sadr. Many Americans were murdered because of this filthy cow plop. Mookie knows that when ISIS comes to his neighborhood, they won't be as concerned about collateral casualties as was the United States Military. ISIS will come in, kill all the males and older females and children, and they will select the younger females for rape prisons and for sale as brides. Mookie can wave bye bye to his wife and female relatives as they are loaded onto rape transport vehicles. And that assumes that he still has a hand to wave with.
I absolutely do not discount Iran entering uninvited if ISIS enters Baghdad in force. What a scenario we are facing now thanks to the ignorant illegal alien in the White House.