"The (Iran-friendly) Shiite majority, which accounts for almost 70% of the population, wants the (Saudi-friendly) king, Sheik Hamid bin Isa al-Khalifa, to rewrite the constitution to give Shiites more power and opportunity, while also seeking investigations into allegations of torture and corruption (sound familiar?).
The downside to all this unpleasantness is that Bahrain is the U.S.'s most important post in the Persian Gulf. It's ground zero when it comes to monitoring the oil flow — nearly one gallon of every five used worldwide — down the gulf and through the narrow Strait of Hormuz. It's also a key base from which to eyeball Iran on the other side of the gulf.
The 5th Fleet and a base used by the U.S. Air Force both call Bahrain home. But the U.S. presence there has always been a sensitive topic. Following World War II, the U.S. had a large presence in Bahrain, but that shrunk in 1977 after Shiite efforts to end the monarchy there failed but succeeded in terminating a docking pact for U.S. warships. But the two sides kissed and made up following the 1991 Persian Gulf War, and the U.S. presence once again blossomed. There are up to 30 Navy vessels in the region at any one time, and they often dock in Bahrain for resupply and R&R."
Read more: http://www.time.com/time/world/article/0,8599,2049458,00.html#ixzz1E4RX65sk