Something to watch closely: unrest in Saudi’s Eastern Province appears to be heating up. In two separate incidents in the last 24 hours, two protesters have died from police gunfire.Saudi Arabia’s Eastern Province is mostly Shiite in faith; the strict Wahabi imams who shape Saudi religious orthodoxy consider Shiites in some cases to be apostates from Islam. Shiites complain about discrimination and lack of opportunity; while the government has spent money on the province to address grievances, it’s clear that not everyone is happy.The Saudis have a lot of money; they can afford to buy off some of the Shiites and hire security forces to deal with others. But the Eastern Province isn’t just home to a restive religious minority; it’s where the bulk of Saudi Arabia’s oil production comes from. Serious unrest there could rapidly change the world’s energy picture.There are enough local grievances to keep the Saudi Shiites stirred up without foreign meddling, but it’s hard to doubt that Iran wouldn’t be thrilled to see its coreligionists rise up against their Saudi overlords at this time of growing tension. Threatening Saudi Arabia at its most sensitive spot would certainly help Iran push back against the Saudi’s clear interest in blocking Iran’s drive for regional hegemony. It would also remind the west that sanctioning Iran isn’t cost free.In the short term it would be surprising if the Saudis fail to maintain security in this restive region. But longer term, the Saudi kingdom is a very strange thing. The Wahabi tribes of the center dominate the Shiite east with its oil wealth, and the traditionally cosmopolitan and broadminded cities of the Hejaz (Jiddah, Mecca and Medina) with their religious prestige and their income from pilgrims. Money and the political skills of the large royal family hold the kingdom together but beneath the surface uniformity, there’s a lot of tension between a kingdom that isn’t a nation.