Uncle Timmy,
To answer 6th gen question about why Saudi would worry:
If the Sunnis are returned to power in Iraq it will certainly assuage the Saudis who now must be terrified of the rise of Shia power and consequently fear, as King Abdallah predicted, the Shia crescent in the mid east growing disproportionately stronger by virtue of its sheer numbers and with Iran's backing.
I would add a following note to your article Chickpea; (for everyone else?s information, I know you know this already)
Saudi Arabia?s oil reserves are not scattered throughout the country but are concentrated in the narrow region along the Persian Gulf coastline.
The two most strategically important nodes in the Saudi oil infrastructure are Abqaiq and Ras Tanura; again, both are located in the Gulf region.
In relation to your article, Saudi Arabia?s Shia minority is also located, primarily, within the Persian Gulf/oil producing region. An uncomfortable demographic fact for the Saudi government.

