Complex web of intra-Islamic enmity snares Middle East
How do we begin to understand the scale of what is unfolding in the Middle East?
The crisis across the region grows by the day.
- Syria is into the fifth year of a war of unrivalled ferocity
- Iraq, hardly stable in any conventional sense, is battling the so-called Islamic State (IS), which is squatting in key areas
- Libya is overrun by militias, with no meaningful civil society
- Egypt, ruled again by the generals, is facing a rising Islamist insurgency that the military is trying to quell through growing force
As if all that were not enough, Yemen is now effectively in the hands of a rebel group that has removed the country's government, prompting a bombing campaign led by its bigger and more powerful neighbour, Saudi Arabia.
Meanwhile, the Saudis, when not bombing Yemen or looking anxiously at the growing influence of Iran across the region, nervously eye their own population for signs of the same popular unrest that a few years ago set in motion the series of upheavals somewhat optimistically called the Arab Spring.
Increasingly, commentators see much of what is happening in the Middle East through the prism of a straight fight between Saudi Arabia and Iran for regional dominance.
This so-called proxy war is conveyed in different ways.
Cold War analogy
Some see it as a sectarian conflict between the Saudis, who are Sunni Muslims, and Iran, a Shia Muslim country.
Others use a different analogy, that of the Cold War, in which two power blocs fight for influence across a swathe of territory, on the guiding principle of backing your enemy's enemy, with every decision informed by the desire to ensure that your opponent does not get the upper hand in the fight for spheres of influence.
In that narrative, Saudi Arabia crushes the Shia protest movement against the Sunni monarchy in Bahrain so that the country does not fall under Iranian influence.
Similarly, Iran backs Bashar Assad's regime to keep Syria as an important ally in the region and stop it falling into the hands of Sunni groups.
Other commentators take the war analogy one step further and claim the Middle East is engaged in a "hot war" between Saudi Arabia and Iran, played out in the continuing military conflicts in Iraq, Syria and Yemen.
All these interpretations disguise other currents and alliances that are gradually emerging - not all predictable and some rather surprising.
So while the Saudis and Iranians fight each other through proxies, they make common cause to destroy IS.
Similarly, in the battle to destroy IS, the US and Iran - long-standing enemies in the Middle East - share a common goal.
Officially, they do not co-operate - that is denied strongly - but there are reports of information sharing through channels.
This causes much consternation to Saudi Arabia, the main US ally in the Arab world, which is not at all happy that Iran's power and influence is growing.
So how big is Iran's influence across the region?
Iran is an important and significant force in Syria, Iraq and Lebanon. In Syria, Iran is providing crucial and significant support to the Assad government.
In Iraq, Iran plays a key role, which includes backing the Shia militias there.
In Lebanon, Iran's writ runs through Hezbollah.
And then there is Iran's continuing support for Hamas, the dominant movement in Gaza.
But Iran is not alone in throwing its weight around and busying itself with strengthening alliances in the region. Saudi Arabia is staking its own claim.
The Saudi-Egyptian relationship is close. Egypt is a major beneficiary of Saudi aid.
Egypt has been important in helping to organise a new regional military force after what happened in Yemen.
This new force is arguably aimed at countering Iranian influence as well as fighting Islamist extremism.
Assad's loss, Saudis' gain
Elsewhere, the retaking of the Syrian town of Idlib in recent days by rebel forces is the first setback in some months for the Assad regime.
And anything that is bad for Assad's prospects is welcome news to Saudi Arabia.
There have been unverified and indeed unverifiable claims - nothing more - of Saudi support for some rebel groups, as well as speculation that the Saudis are working much more closely with Turkey in protection of mutual interests in the region.
But it is fair to say that the Saudis are no longer averse to finding new ways of asserting themselves across the entire region.
There is a belief among some analysts and commentators that, in the shifting landscape of the Middle East, there is a desire for more autonomy among Sunni Arab states, and a gradual loosening of ties with their traditional ally, the US.
The unfolding conflict in Yemen provides another insight into the calculations and rivalries fuelling the instability in the region.
Even here, things are not as straightforward as they might appear. Yemen, which has a Sunni majority, is unstable and dangerous.
The country has been the base for al-Qaeda in the Arabian Peninsula, one of the most dangerous of the al-Qaeda affiliates.
The rebel Houthis, now attracting worldwide attention, are indigenous to Yemen and are a hardy fighting force.
They know the terrain and in the past decade or so have fought several small-scale battles across the country.
Again, some analysts see Yemen as the victim of a proxy war between Saudi Arabia and Iran.
The narrative works like this.
The Houthis follow a form of Shia Islam (so are on "the same side" as the Iranians) and are guilty of displacing the Saudi-backed Sunni government of Yemen, something unpalatable to the Saudis, thereby leading them to undertake military action.
The proponents of the proxy-war scenario say that neither side can back down over Yemen, so how does it end? Is it open-ended?
The Saudi foreign minister spoke of a Yemen "returned to security, stability and unity" but with no detail on how long that might take.
The Iranians have denied military involvement in Yemen but Iran admits backing the Houthis financially.
It is hard to know the truth. However, some analysts agree that the Iranians provide money but do not control the Houthi rebels in the same way as their other proxies, such as Hezbollah.
The countries taking part in the bombing of Yemen is an instructive list.
The Arab coalition is a feat in itself, given the dismal record of Arab nations in the past when it comes to co-operating with each other.
- Saudi Arabia
- the UAE
The development of this sizeable grouping runs the danger, according to some who watch the region, that the bombing will slowly but surely turn a civil conflict into a larger Sunni-Shia war with Iran.
Alliances of convenience
Any account of the current crisis in the Middle East has to mention Iraq.
The conflict there has sometimes slipped under the radar for periods, until the IS announced itself by routing Iraqi Government forces and taking Iraq's second biggest city, Mosul.
As a result, in today's Iraq, the US finds itself fighting IS alongside Iran.
US officials deny co-operating with Iran as such.
Yet the recent US bombing of Tikrit underlines some of the alliances of convenience and the uncertain consequences.
The strategically important Tikrit - Saddam Hussein's home town - is in the heart of Sunni territory in central Iraq.
It is the gateway to the bigger city of Mosul and the eventual military goal of retaking it from IS.
But the US runs the danger of being seen to side with Shia militias - who make up the bulk of the military forces battling IS - over Iraq's Sunni population.
These very same Shia fighters face accusations of a terrible human rights record and a propensity to sectarian bloodshed.
The other danger for the US is that the Shia militia will capture too much of Iraq's territory in the fight against IS, further alienating Iraq's Sunnis.
And according to some analysts the US-led campaign in Iraq is effectively bolstering the Assad regime in Syria by weakening its most dangerous enemy, IS.
That would be the very Syrian regime that the US has spent so long trying to dislodge.
It is fair to say that the Middle East is never far from the minds of political leaders the world over.
But there are, as ever, other pressing distractions.
President Obama is coming to the end of his second term and has been focused on the Iranian nuclear question.
Britain is in the middle of one of the most closely fought election campaigns in living memory.
And the big European powers are worrying about Vladimir Putin's Russia.
A news story in the Guardian newspaper in recent days conveyed the drip-drip effect of years of conflict and how remarkable stories eventually become commonplace.
The story was about the collapse of the education system in Syria, with at least a quarter of schools damaged or destroyed, with enrolment rates at 50%, down from the pre-war levels in which nearly all Syrian children went to school.
The information came from a report from the Save The Children charity.
In normal circumstances such a story might be expected to provoke widespread comment and all kinds of questions. But terrible stories emerge almost daily from Syria and this one just ended up as one more tale to add to the growing list of human tragedies across the region.