Leading article: Where winter is freezing the Arab Spring

President Bashar al-Assad has managed something almost inconceivable in this age of mass communications: by dint of denying foreign journalists entry, he has effectively sealed Syria off from the outside world. But what news emerges veers from the extremely bad to the utterly appalling. Most recent reports focus on the north-western town of Jisr al-Shughour, where 120 people were reported killed. Some, if not most, of the dead may have been troops or members of special forces shot for refusing orders to fire on civilians (or, as another version has it, in order to prevent them from opening fire).

Whatever happened in Jisr al-Shughour, however, is just the latest outbreak of violence instigated by a regime ruthlessly clinging to power. And a UN Security Council resolution drafted by the UK and France is little more than an exercise in hand-wringing. It nonetheless risks a veto from China and Russia, which still regard a Syria with its current, ever more repressive, President in place as preferable to a Syria without him. Given that the United States and the Europeans have neither the appetite nor the capacity for new military intervention, this increasingly vicious and costly struggle looks set to go on.

It is not unreasonable to ask why intervention was mounted to protect civilians – and assist anti-regime forces – in Libya, but is ruled out in Syria. The simple answer is: because advocates of that intervention judged it to be feasible, and because there was an immediate, and defined, threat that could be averted. Even with this limited objective, however, it appears they may have bitten off more than they could chew. Syria would be a step considerably too far.

Yet the implications of chaos in Syria must be considered, and urgently. Recent attempts by Palestinians to breach the border with Israel and the swelling stream of refugees arriving in Turkey and Lebanon warn of the potential for unrest in Syria to destabilise the whole region. The time may already have passed when political concessions from the regime to the variegated opposition will make any difference. But without them, the escalation of violence looks impossible to avoid.