Obviously, OPEC nations have a strong incentive to see oil prices above their breakeven prices.

The lowest is Kuwait, at just under $65. Saudi Arabia, which supplies 10 percent of U.S. oil (the most among OPECers), needs $80 a barrel.
Sinn thinks we're unlikely to see oil prices below $70.
To be sure, oil plummeted down to $36 in Jan. 2009. But just two years later it had shot back up to $100.
Should the West impose sanctions (the EU will make a final decision later this month), the price will likely climb even higher (although given Iran gets 60 percent of its GDP from oil revenues, as Fareed Zakaria recently pointed out, Iran is in fact unlikely to respond by closing the Strait of Hormuz). The threat of sanctions has already done so.