To the degree that such fire-sale prices are long-lived, they could cause mayhem among petro-rulers. While Verleger thinks that the Saudis can maneuver prices back up when they want, the very nature of a crash demonstrates that markets can be uncontrollable. But the Saudis are willing to suffer the consequences, knowing that their own financial reserves (some $700 billion) give them staying power. "The Saudis are able to look at the long term," Phil Flynn, an analyst with Pricing Futures Group, told me.

Citigroup's Morse thinks that prices can fall further from where they are now, but not as low as Verleger forecasts because, he told me, today's market conditions are different from 2008 -- the decline in demand is not as steep, and inventories are not as large. Morse calculates that Brent can fall into the $70s-per-barrel range and U.S.-traded oil into the $60s-a-barrel range. "There is a good chance Saudi Arabia continues to produce enough to force [a rise in oil inventories]. And there's a good chance, between Europe and China, that demand growth could come to a halt," Morse said. OPEC might respond by reducing production, but its actions would be late. "Add to the scenario no more supply disruptions (or only modest ones) and no military conflict involving Iran," Morse said, "and prices could fall another $20 a barrel fairly easily."

Low oil prices can have serious social impacts simply because, with less free cash, people tend to start more closely scrutinizing their surroundings -- and when they become unhappy with what they see, they start looking for a scapegoat. The conditions that led to the string of Arab Spring ousters were not so much the lack of democracy as widespread public dissatisfaction with personal economic prospects. Analysts see similar vulnerabilities for the rulers of Iran, Russia, and Venezuela; when Venezuelan President Hugo Chávez can no longer milk the state oil company for public payouts, for instance, his political support could be in jeopardy.