Syria: Why Houla massacre may not lead to intervention
The road to war is paved with massacres.
Traditionally, the symbolism of mass killings - whether imminent, as in the Libyan city of Benghazi last year, or complete, as in the Bosnian town of Srebrenica in 1995 - has bridged the gap between diplomacy and military action.
Will the Houla massacre in Syria this week, apparently involving the killing of so many children, have a similarly catalytic effect?
Nato officials insist that they have not been planning for intervention in Syria.
American officials have been cagey. Some Arab states - notably Saudi Arabia and Qatar - have been urging the use of force, but have confined their intervention to weapons and cash.
But, although the gruesome footage emerging from the town of Houla will generate fresh pressures on all these countries to rethink their caution, the result is more likely to be intensified diplomacy than a rush to war.
One thing is clear - the Houla massacre kills off a ceasefire that had long ceased to have any meaning.
There are echoes here of Srebrenica in 1995, when UN peacekeepers could only look on helplessly as Bosnian Muslims were slaughtered.
In Syria, the UN monitors had been denied access to the area on Friday, when shelling of the town began.
The UN mission has been undersized and under-resourced. Its impotence in the face of such violence means that there is no incentive left for Syrian rebels to pause their own campaign.
The Free Syrian Army (FSA) - a Turkey-based umbrella group for rebel fighters - has declared that, "unless the UN Security Council takes urgent steps for the protection of civilians, Annan's plan is going to go to hell".
In truth, it is not even clear whether the FSA is in control of local fighters - meaning that this conflict will have a momentum of its own, irrespective of what the opposition leadership wants.
So far, though, there is no sign that Houla will be a game-changer.
First, remember that this massacre will be interpreted differently around the world.
Many countries sympathise with the Assad's government narrative that the opposition are Arab-backed Sunni fundamentalists and terrorists.
Gen Robert Mood, head of the UN mission in Syria, has said that the circumstances behind the killings remain "unclear".
Just as some critics argue that the massacres in Libya last year and Racak in 1999 are exaggerated or fabricated, similar scepticism about Houla will persist, even in the face of incontrovertible evidence - and that will affect how the UN Security Council lines up on the issue.
Moreover, the growing role of al-Qaeda and affiliated jihadist groups in Syria has, in recent months, become a further deterrent to intervention.
American officials are terrified that support for the opposition may end up in the hands of the very same people that mounted attacks on Western forces in Iraq just a few years ago.
Policymakers also worry that any Western boots on the ground - even in a so-called safe-zone - would be vulnerable to bombings, like the the 1983 Beirut barracks bombing that killed 241 US servicemen.
Above all, however, no-one wants to pick a fight with Russia.
For instance, if Russia continues delivering arms and aid to Damascus, it is inconceivable that Nato would interdict these, and risk escalation.
US diplomats are now hoping that Moscow might be persuaded to ease Assad out, but keep the regime - and Russian interests - in place.
This is a scheme modelled on the way in which the US and Saudi Arabia coaxed President Ali Abdullah Saleh from office in Yemen earlier this year.
This is unlikely to work. The regime is highly personalistic, and would probably unravel quickly without Assad and his core advisors.
The rebellion is also at an advanced stage, and will not acquiesce in a squalid compromise that might even leave the perpetrators of this massacre in charge of the security forces.
The Houla massacre is only the latest, if most grievous, of developments that make a mockery of Kofi Annan's peace plan for Syria.
If even the most basic of its terms - a ceasefire and withdrawal of government forces - will not be enacted, a negotiated political transition is futile.
In the short term, Turkey and the Arab states are likely to increase the material assistance to parts of the Syrian opposition.
If diplomatic efforts do not bear fruit quickly, the other "Friends of Syria" - including the US and Britain - may follow suit, in the absence of the political stomach for a real war.