Well, you are asking several different questions there, all of which have different or many answers. Read your two posts. You go from: Who started ISIS? What disaffected group? What former group of military folks from Iraq advise ISIS? How did that group become disaffected in Iraq? All the way too in response to Gr8:
Wow...so you are saying you don't know that it was former military leaders under Saddam, Sunnis, who are helping ISIS now? Really?
There is a big difference between who started it and who is helping them, and how much the aforementioned Iraq military leaders are needed, .
Al-Baghdadi, the self proclaimed caliphate was thought to be a revolutionary Isamic professor(sunni) well before ISIS started and some even think before he invasion. No one knows for certain. If the USA would have known more-they likely sent him to Gitmo rather than release him. Much of ISIS is made of Al Qaeda and fighters that came from al-Nusra, and ME/North Africa region recruits. Large foreign influence. But pretty much all the main players had ties to Al-Qaeda, Afghanistan mujahideen, Chechen fighters, and Syrian rebels. Al-Qaeda(mostly Sunni), Afghanistan mujahideen were around long before the US invaded Iraq. Not like the USA invasion created those groups.
Sure former Baath party and Iraq military officers(sunnis) are helping ISIL. However, they also have Afghanistan mujaideen that were trained by and fought against the USA, fighters from the Georgian Army(mainly Chechens) that were trained by you guessed it, the USA and Russia, and Syrian rebels who have been trained by the USA, UK, and Russia(when they were part of Syrian Army).
So the answer in short to all your questions/claims would be nobody really knows for certain how it started, or would it have started. But as of now from reports on the ground it is pretty obvious that there is enough well trained military leadership with a vast background in training and philosophies to be good in battle without any former Iraqi officers.
And that is just the tip of the ice burg. Anyway, a big stretch to go from who started it to who is helping them. When you stated that Gr8 did not know it was former military leaders under Saddam Sunnis, who are helping ISIS, you seemed to imply that they needed that help to be successful or exist. Not the case. I mentioned all the foreign fighters and foreign training they had. I am sure they like the former Baath military officers-not needed though. It is a tough group, and SF guys on the ground there all say in every location they have their act together.
"Some organization like ISIS would have probably formed, but would they have declared a caliphate and swept across half of the country and captured major cities?" (Gr8)
Read that again, and then read why most of what you typed is nonresponsive to that. So, areas of agreement, ISIS would have formed regardless. Area of disagreement, they wouldn't have swept across Iraq and captured cities but for Obama. What did I point out? Actually, the reason why they were able to capture cities is because of the help of former Baathists...and I linked Fox News of all places for that very point that ISIS needed that help to capture cities. I said nothing about "ISIS needed Baathists to exist." Gr8 admitted that ISIS in some form would have existed regardless. So, as usual, you ignore the specific thing talked about and assume some giant broad point was being made that no one made.