My mom out in California is elated -- gasoline prices in her neighborhood are below $4 a gallon for the first time in four months. Less so are the world's petro-rulers, who are watching the price of oil -- their life blood -- plunge at a rate they have not experienced since the dreaded year 2008. Industry analysts are using phrases such as "devastation" and "severe strain" to describe what is next for the petro-states should prices plummet as low as some fear. No one is as yet forecasting a fresh round of Arab Spring-like regime implosions. But that's the...