Can Syria avoid sliding into 'catastrophic civil war'?
Horrified by the Houla massacre, other atrocities and the remorseless daily violence, the outside world is desperately casting around for a way to prevent Syria from sliding inexorably towards a disastrous civil war, and to secure the launching of some kind of political process.
But despite huge international frustration, it keeps coming back to the same thing: at least for the moment, there is no alternative to UN-Arab League envoy Kofi Annan's peace mission, which has made little headway despite enjoying the support of the entire world, including, at least in theory, the Syrian regime.
Mr Annan's talks with President Bashar al-Assad in Damascus on Tuesday have failed so far to produce any sign of the "bold steps" that he wants the Syrian leader to take to demonstrate that he is serious about implementing the six-point peace plan.
By the time he found himself repeating that plea for "bold action" from Mr Assad three days later in Beirut, confessing himself "frustrated and impatient", Mr Annan had dropped reference to the need for the opposition side also to fall into line.
His public focus was clearly on prodding the regime, as the stronger party, to take significant steps such as withdrawing troops and heavy weapons back to barracks - something that should have been implemented weeks ago as the first stage in pacifying the situation on the ground.
That has not happened, despite written assurances from the Syrian foreign minister to Mr Annan in April that it had.
The regime is concerned that the resulting vacuum would be filled by rebel fighters or otherwise go over to the opposition, and that it would lose control of substantial parts of the country.
In other words, as events on the ground have indicated, it cannot afford to implement any peace plan that requires withdrawing the military, because that would be to seal its own fate.
Which leaves Mr Annan trying against the odds to convince the regime that the opposition would respect a truce - and that countries backing rebel fighters would halt the flow of arms to them.
Hence, after Damascus, his visits to the countries neighbouring Syria, where his talks focused in part on efforts to stop arms smuggling across the borders.
Achieving the reality, or even credible assurances, of that happening, and being able to persuade the regime to put away its troops, tanks and artillery, seem pretty forlorn hopes, given the venomous and worsening situation on the ground.
What seems to be missing from the equation at the moment is the kind of pressure on Damascus from Russia that was crucial in persuading the regime to accept the Annan plan in the first place, and to drop impossible conditions it later placed on implementing it.
For the time being, despite mounting international pressure on their own position in the wake of the Houla massacre, the Russians are continuing to argue against the idea that the UN Security Council should consider tougher action such as mandatory sanctions.
Blocking off such action increases the onus on Moscow to help secure Syrian compliance with the Annan plan, which the Russians continue to insist is the only way forward.
If Syria is indeed now bent on a downhill course towards disintegration and an ugly and protracted sectarian civil war with dire regional consequences, Russia may soon have to choose between trying to foster a peaceful and serious transition in the hope of salvaging a relationship with whatever Syria emerges from the crisis, and sticking by the current leadership whatever the cost as things fall apart around it.
After months of bloody stalemate between an uprising that would not go away and a regime that seemed immovable, there are some signs that things may be starting to change.
For the first time, the Sunni merchants in the souks or markets of Old Damascus - previously a staunch pillar of support for the regime - have for the past several days shut up shop and gone on strike over the Houla massacre, despite attempts by regime enforcers to make them reopen.
That could mean that a combination of economic collapse and sectarian atrocities may have carried dissent into the heart of the capital and the core of the regime's power base.
Some Damascus residents say that the shabiha militia has taken on a high-profile repression role in the centre of the city, dressed in the uniforms of riot police and alienating the middle-class public by brutal and intrusive behaviour.
The regime's sense of vulnerability and readiness to lash out may have been aggravated if it is true that some of its insiders - including the President's brother-in-law Assef Shawkat - are still seriously ill after being poisoned by an opposition infiltrator at a top-level security meeting last month.
The initial opposition claims, on 20 May, were denied and ridiculed by the authorities, but some sources have said it is true.
Whatever the case, the level of hostilities around the country has been creeping back towards - and sometimes beyond - where they were when the Annan truce came into effect on 12 April.
And events such as the Houla massacre and other atrocities attributed by the opposition to the shabiha - a regime militia drawn almost entirely from the Alawite minority from which Mr Assad's ruling clan hails - have intensified the already strongly sectarian aspect of a struggle in which the uprising is by its nature based largely among the poorer sections of the majority Sunni community.
This is why, as daily violence continues relentlessly, the alarm bells have begun to ring so loudly in chanceries around the world.
For if Syria, with its patchwork of sects and minorities, descends into open-ended confessional strife, it could, as UN Secretary-General Ban Ki-moon warned, be plunging into "a catastrophic civil war from which the country would never recover".
Lebanon, just next door and sharing many of the same confessional fault lines, provides a stark example.
It erupted into sectarian strife in 1975, ushering in 15 years of conflict and opening rifts which still threaten to explode today.
For the same thing to happen in Syria would have incalculable consequences not just for the country itself, but for the wider region. That is why world leaders are so alarmed. But they seem powerless to stop it happening.