The long-nurtured religious and clan hatreds damning Syria seem incomprehensible to 21st century Americans and Europeans. The US, Russia and United Nations are very keen to hold a peace conference to end the Syrian war because of deep shock at its barbarity and carnage among innocent civilians. But a UN meeting this week could not find relevant takers among the warring factions.

The urgency for peace was heightened by French and British assertions this week that nerve gas has already been used in Syria (although they did not identify the chain of custody or who deployed it). Yet, militants opposing Syrian President Bashar al Assad are so fragmented that the peace conference planned for June has been deferred to July and may not occur at all.

The keys to Syria’s wars are held by various militias acting as proxies for Sunni Saudi Arabia and Shia Iran, with a few pro-democracy moderates being proxies for the US wars on totalitarianism and anti-West terrorists.

For Saudi Arabia and Iran, the war in Syria is not against anti-West terrorists. It is a long war between Sunni and Shia Islam for ascendency over the global Muslim “family”. That war began in 661 AD.

If at all, Washington should step warily into this cauldron marked by irrationality and antiquated vendetta among the local players. The only exit is to find ways allowing Sunni and Shia to live together in peace because this not just a matter of dethroning a tyrannical dictator in Damascus.

Teheran’s mullahs see Syria as the buffer zone in a war of survival for Iran as a home of Shia Islam. Those orchestrating the onslaughts are heavily armed and very wealthy Sunni Arab states. To add to the mullahs’ nightmare, the world’s greatest ever military and economic power, the United States, is very liberally arming and training their enemies.

It is quite likely that Iran’s Mullahs will renounce the nuclear weapon if their faith is made safe from Sunni extremists. Teheran needs to deter Saudi-backed Sunni power, not Israel.

The Iranian regime is inflamed because Saudi Arabia’s Wahhabi and Salafi charities are encouraging an al Qaeda affiliate, the al Nusra front, to capture Syria for radical Sunni Islam.

Teheran is maneuvering to prevent strangulation by radical Sunni Islam in Kabul and Islamabad on the one side and Saudi Arabia, Qatar and al Nusra on the other. Wahhabi and Salafi Sunnis detest the Shia and Pakistani Sunnis regularly destroy Shia mosques and murder Shias, usually with impunity.

If the Shia-affiliated Alawite regime of Bashar al Assad falls in Damascus, the ensuing chaos may bring al Nusra to the forefront because Syria’s Sunni majority widely admires their fighters’ bravery (although it also fears their religious intolerance). Such a victory could resuscitate al Qaeda worldwide in various forms, including self-radicalized militants.

Taking sides in Syria or punishing Iran may quiet one war in a very long series since 661, when the Shia faith’s founder, Imam Ali, was assassinated in the Saudi peninsula and his son Hussein fled into Iraq with his followers. From Iraq, the religion spread to Iran, which has fought countless wars to protect its faith against Arab assailants.

In 680, Ummayad forces captured and beheaded Hussein at Karbala in Iraq because of his Shia beliefs. The Ummayads were a Saudi clan from Mecca, which ruled one of the world’s largest Sunni empires from Damascus, Syria, in the seventh and eighth centuries. (They are said to have descended from an illegitimate son of the Prophet Mohammad’s great grandfather. Imam Ali was a descendent of the legitimate son, whose Hashemite clan now rules Jordan.)

Neither conservative Sunni nor Shia has forgotten 680. Syria is the current crucible. Meanwhile, Osama bin Laden’s al Qaeda is crippled but his radical versions of Sharia law are alive and strong. They are now spreading to affiliates and self-radicalized individuals like the two boys who killed three and wounded 264 in Boston on 15 April 2013.

Partisans of Sharia law run into hundreds of millions. Pew Forum research published in April 2013 shows that 81% of Pakistanis and Jordanians say Sharia is the revealed word of God, as do clear majorities in most other countries surveyed. High percentages support making sharia the official law, including 99% in Afghanistan, 84% in Pakistan and 82% in Bangladesh. About 40% in the Middle East think that Sharia should apply to non-Muslims, rising to 58% in Jordan and 74% in Egypt. These are the views mostly of Sunnis, who comprise over 90% of Muslims.

The remaining 10% is mainly Shia. They comprise 89% of Iran, 60% of Iraq and small majorities in Yemen, Azerbaijan, and Bahrain. Sizable Shia minorities live along the east coast of Saudi Arabia, in Lebanon and in India (probably 60 million).