You can’t tell the crises apart without a scorecard. So Bahrain has gotten lost in the shuffle a bit. But as we saw yesterday, Saudi troops have been dispatched to help put down a largely sectarian uprising, with an oppressed Shiite majority seeking greater rights and participation from the ruling Sunni minority. And now, the nation has declared martial law.

The streets of Bahrain’s capital, Manama, have again erupted in violence as the kingdom’s besieged monarch declared martial law and ordered troops – including Saudi forces – to take all measures to quell a festering rebellion.

The clashes had been anticipated since more than 1,000 troops from Saudi Arabia and other Gulf states arrived in Bahrain on Sunday, after being invited by the ruling dynasty to help restore order.

Demonstrators and security forces faced off from mid-morning in the Sitra area on the outskirts of Manama. Bystanders reported the sound of gunfire and the scent of teargas by early afternoon, followed by the familiar cacophony of ambulance sirens as they sped casualties towards the city’s two main hospitals.

By late afternoon, there were numerous reports of clashes inside Shia villages throughout Manama that had led to dozens of injuries.

In addition to an extension of the struggle for human rights by the citizens of the Arab world from its rulers, this is a proxy battle, part of a regional jockeying for power between the Saudis and the Iranians. Bahrain recalled its ambassador to Iran after the Iranian foreign minister made a pretty muted statement about Bahrain’s ruler needing to act with “wisdom and caution”.

The US has urged “restraint” in Bahrain while sending emissaries like Mike Mullen and Robert Gates to show support for the ruling regime. They clearly want to hold the Fifth fleet naval base, and will turn a blind eye to the horrific violence that has already occurred. But the sectarian component of this uprising brings up another point. This was essentially predicted by events in Iraq in 2003. That upset the regional balance of power and ended up tipping the nation to the Shiites, expanding Iranian dominance over the region. The Saudis were alarmed at this, and needed to assert their own power as well. That has now played itself out in Bahrain, where you have a regional proxy battle, perhaps the first of several in the Middle East. Back when the Bush Administration invaded Iraq, many talked about destabilizing the region. I think this is what they meant.