Personally I have no idea, but here is an opinion:

Why the Iraqi army collapsed

Quote Originally Posted by Bill Moore View Post
Does anyone know why the Iraqi military didn't resist? Maliki claims it was a conspiracy, and in this case that makes sense, but who were the conspirators and why?

Wild spectulating on my part.

- this ties into the Arab coalition trying to oust Assad. Supposedly Maliki has been helping Assad with his Iranian buddies.

- a state actor out of the region enabled ISIS and paid off Iraqi military leaders to not resist to put Iraqi oil at risk to strengthen their position in the global market, which makes boycotting them impractical.

I have absolutely no supporting evidence for either hypothesis, but for the better equipped and trained Iraqi army to just drop weapons and flee due to a irregular force advance doesn't add up.