DAMASCUS // Violence has been plentiful in Syria over the past 15 months, the early trickle of blood swelling to a deluge as killing became something that happens every day as surely as the sun rises and sets.
But against this gruesome backdrop of carnage, horror and grief, the massacre in Houla on May 25 still stands out. It now has a special resonance: an atrocity even among atrocities.
At least 108 people, mostly women and young children, were executed by gunshots to the head, butchered by the slash of a knife blade to the throat or cut down by shellfire as they cowered in their homes. Survivors have described how they smeared themselves in the blood of their relatives and played dead as the killers swept through.
"There was before Houla and there is after Houla. Something has changed, we can all feel it," a Syrian friend said in Damascus the other evening. "Things will never be the same again".
Before, he had always been optimistic about the outcome of the revolution-in-progress. He saw the uprising as his country growing up, shaking off a decades-long coma. He would always brush aside the notion his country might go to war with itself, and certainly not slide into a sectarian war.
In post-Houla Syria, that confidence has faded. "There is so much anger and fear, anything is possible," he said.
Another man I speak to fairly regularly, a cheerful supporter of the Syrian president Bashar Al Assad, was quiet and despairing in the massacre's aftermath.
"I thought we would escape the worst of it, but it's coming our way. It's just a question of time," he said.
In the days after Houla, the intensity of protests and anti-regime militancy appears to have increased in Damascus and the city's volatile surrounding suburbs, as if the stakes have markedly risen.
Peaceful snap demonstrations now pop up in the city centre with more frequency. At a protest last week next to the Italian hospital, in the busy Hamra Street market, security forces started shooting, forcing screaming afternoon shoppers to run for safety. The awful sound of gunfire is no longer limited to fringe neighbourhoods.
There was fighting in Midan - not protesters being fired on, but fighting between armed rebels of the Free Syrian Army and government forces. Midan is not some obscure, distant edge of Damascus. It is a district populated by well educated, middle-class families, a few minutes' drive from key security offices, government buildings and the very heart of the Syrian capital.
A shopping mall in the upper-class Maliki neighbourhood - very much home of the ruling elite - was briefly and discreetly closed last week, apparently after three explosive devices were found there.
Traffic along major roads into Damascus is halted on a routine basis, not only by official security-force checkpoints but by blockades thrown up by protesters. The newly laid tarmac on the international highway connecting Damascus to Jordan is already pitted and scarred from burning-tyre and rock barricades, which these days are erected not only at night but in broad daylight.
"The crisis used to be in Homs and a few other bad areas, now it's everywhere," said another man in his twenties whom I meet regularly. He is also a devoted fan of Mr Al Assad, and whenever we talk he has always happily predicted the impending end of the revolt and jauntily promised to lay down his life for country and leader.
"I don't know what the future will be now. It's black. I will be killed or I will have to kill - a war, maybe. I don't know what is happening to my country," he said in a late-night conversation.
There was no exuberance in his voice, no thrill at the prospect of a call to arms. Only a sober recognition that the prospect of actually having to fight was suddenly close at hand.
In their unspeakable, apocalyptic brutality, the events in Houla have served as a blunt reminder to Syrians that there are no depths to which some of their compatriots will not sink to inflict pain and suffering on their countrymen.
It also speaks to the darkest side of Syria's burgeoning fission - an incipient sectarianism that, if manipulated or allowed to grow, could pit the Sunni Muslim masses against the Alawite minority in a bloody war of attrition.
Yet if Houla has given Syria a glimpse into the abyss of an horrific future, it does not seem to have induced those with influence over the course of events to seek a less violent alternative.
Supporters of Mr Al Assad, particularly among the Alawites - those who believe the official explanation that Houla was the work of foreign-backed Islamist extremists - take it as confirmation that hordes of Sunni terrorists are truly rising up to slaughter them.
For those opposed to the regime - those who believe the testimony of Houla residents and activists that a notorious pro-Assad militia was responsible - it reinforces their view that they are facing a merciless, amoral enemy who will stop at nothing to cling to power and privilege.
Instead, what before Houla was already the slim prospect of a political settlement now appears more unlikely than ever, swamped by the logic that, for either side, compromise would mean subjection or, worse, annihilation by a foe capable of immeasurable cruelty. It is the logic of war.
Wars probably don't ever start with a single incident. They instead result from a steady accumulation of events. But there comes a moment where history judges that the conflict really began, when the point of no return is left behind and the path of war irrevocably set upon.
In Damascus these days it is difficult to shake the ominous feeling that, in Syria's case, historians might look back and mark that moment as Friday, May 25, in Houla.
