As protests roil the Middle East, most commentators are focused on countries like Yemen, Iran, and Algeria—but the real action may be happening in tiny Bahrain. The Persian Gulf statelet is home to the U.S. Navy's Fifth Fleet and a smattering of other American military personnel, but the island kingdom has another, potentially more important claim to fame: It is seen as a harbinger for Saudi Arabia's oil-rich Eastern Province.

As with the Saudi Arabian desert governorate of al-Hasa, Bahrain's largely Shiite population is under the control of a Sunni monarchy. Saudi Arabia's grip on its vast oil wealth would be threatened if ideas about self-rule spill over to its Eastern Province, and so the House of Saud has cultivated strong ties with Bahrain's ruling Al Khalifa family. The rulers of Bahrain have until now kept a lid on the situation through a carefully calibrated combination of carrots (oil-financed handouts) and sticks (fomenting sectarian strife), but that stategy might not hold up to the revolutionary tide sweeping the Middle East. As Gala Riani with Jane's Defence Weekly told the BBC, "The authorities will be able to handle it, as they have in the past, if it is sectarian in nature," but with crowds chanting "neither Sunni nor Shia but Bahraini," that's a conditional that may no longer hold.

The big question now is whether or not there will be a Saudi intervention. The kingdom showed a willingness to intervene in favor of its allies during the Egyptian crisis when it floated the idea of making up America's military aid to Egypt if the flow were cut off, and the BBC is citing both Riani and an unnamed "expert with close ties to the powerful Saudi Interior Minister Prince Nayef" as saying that the Saudis are prepared to intervene if the situation "gets out of hand." The subscription-only Tactical Report is claiming that the Saudi interior ministry already has plans to ship anti-riot gear to its counterparts in Bahrain.

As Cairo-based blogger Issandr El Amrani has pointed out, the U.S. State Department has been very critical of the Iranian regime's crackdown on protests, while only offering tepid support for the protesters in Bahrain, even as the death toll in the island kingdom has risen above that of Iran. If the situation in Bahrain does indeed get "out of hand" and the Saudis intervene, America could find itself in a very sticky situation, balancing the interests of its Saudi client state on the one hand with its supposed commitment to fostering democracy on the other.