If Russia takes Iran - they will move on Saudi Arabia, Kuwait, all the way down until they have a clear and unobstructed route into the Indian Ocean. Their influence will then move Westward - something they were trying in the eighties, but really did not know how to approach it.
Why move on a country when the country will destroy itself - makes perfect sense.
The Global Security article points to just that in so many words...makes one think the intel analyst know more than what is put out...