At the heart of the Bahrain crisis is a Sunni / Shia Muslim split that is not limited to the small island off Saudi Arabia, but extends throughout the Persian Gulf region, home of most Arab oil wealth.
The Sunni al-Khalifa family has ruled Bahrain since 1782 despite a clear majority of the population being Shia.
There have always been tensions between the two communities, with the Shia accusing the royal family of packing the higher echelons of the security forces, government and business community with Sunnis.
The Iranian government is giving support to the Shia population while Saudi Arabia and Pakistan side with the Sunni al-Khalifas. Add to this that the US Navy's 5th Fleet is based in Bahrain, partly to counter Iranian influence in the Strait of Hormuz, and a small island's domestic political situation becomes of major regional geopolitical importance.
Bahrain gained independence from the UK in 1971 and became a parliamentary monarchy, but in 1975 the then King moved against Shia unrest by declaring the island an absolute monarchy.
There were violent demonstration during the 1990s as the Shia demanded more rights, these were brutally suppressed, but in 2001 the pressure was so great the ruling family allowed parliamentary elections.
Despite this, the Shia opposition parties maintain that the system is still rigged against them, noting that they remain a minority in parliament, and that, as the Republican Tea Party movement wants to re-introduce into the US, the upper chamber is appointed directly by the king and thus blocks reform.
Given this key dynamic, the Iranians, Saudis, and Americans are watching the unrest in Bahrain with intense interest.
The Iranians have long laid claim to the island, and would be pleased to see the Shia majority there in charge to compliment the growing Shia power in Iraq and Lebanon.
That, and the fact that the Saudi Arabian oil fields lie in the part of the kingdom which are dominated by Saudi's Shia minority, explains why Riyadh is backing Bahrain's royal family with expertise and it is rumored military hardware.
Much of that hardware will originate in the US, which wants to maintain its naval presence in Bahrain.
The protests are not entirely down to the Sunni / Shia split.
Those demonstrating may be mostly Shia, but they have similar grievances to many other Arabs across the region; unemployment, poverty, lack of free speech and social freedoms.
However, MOST demonstrators are Shia and overwhelmingly those cracking down on them are Sunni. The protesters face a problem not seen in the other Arab countries.
Bahrain's capital, Manama, does not really have a city centre, nor a symbolic focal point for rallying. The demonstrators had been mostly gathering in small Shia villages near the capital.
They then hit on the idea of going to the Pearl Roundabout in the shopping area on the outskirts of the capital.
This resulted in the vicious crackdown in the middle of the night, according to this piece from, of all, places, Sky News.
The subsequent loss of life risks turning what began as protest for greater democracy, into outright calls for the royal family to be overthrown.
David Caploe PhD
Chief Political Economist