The town of Khan Sheikhoun in Idlib – men, women and children lying on the streets gasping for breath, faces turning blue, foam gurgling from mouths, rescuers, many also afflicted by the deadly white-yellow gas, tearing off the clothes of the dying and washing down their agonised, contaminated bodies with hoses, bombed hospital wards and desperate doctors scrambling to aid choking children as the dead accumulate ... These have been some of the most shocking and distressing broadcasts we have seen yet from Syria; beyond, many might feel, the acceptable. But we must see them to truly understand this.
Words are not enough to describe this toxic kill zone, this war crime. And now we, the international community, must find some means of holding the perpetrators to account.
There can be little doubt about who was responsible – despite outrageous Syrian and Russian attempts to blame rebels; alone the Syrian air force has the capacity to carry out the aerial attack and the expertise to develop and weaponise illegal chemical weapons, believed to be sarin.
Aside from the utter brutality of the attack, what is almost as shocking is the apparent sense of total impunity and unassailability Syria's President Bashar al Assad clearly feels. And what it says about how far from any prospect of regional peace we are. In the wake of his use of sarin in 2013, when hundreds died in an attack on a Damascus suburb, Assad was forced to renounce and hand over ostensibly all of his chemical weapons after Barack Obama threatened an air campaign to topple him.
Since then, and more recently, his murderous hand may also have been stayed by international pressure to take part in faltering peace talks overseen by the UN in Geneva and by Russia and Turkey in Astana, Kazakhstan. These had been partly premised on demands for his departure as a precondition of any deal. But Assad, increasingly confident that he will not be militarily defeated – not least because of assistance from Russia and Iran – has also seen a political tide turning in his favour.
Western countries, including the US, which have begun to see him more as a potential ally against Islamic State, had been quietly dropping their demands that he leave power in any deal to end the war. And that tide had been reinforced with the election of Donald Trump who has described Assad's hold on his office as "a political reality". In the presidential election, Trump repeatedly criticised Hillary Clinton and Obama for pushing for "immediate regime change in Syria". However, last night Trump appeared to be shifting his ground in response to the massacre, suggesting that he may take a new view on Assad.
Until today, Assad could see the way the wind was blowing. There has been no one to cry halt. The old impunity has been restored. And the mask has slipped.