Gruesome Syria video pinpoints West's dilemma
The video which appears to show a Syrian rebel taking a bite from the heart of a dead soldier provides a shocking punctuation mark in the more than two-year-long struggle for the future of Syria. It is a reminder of the horror and bestiality of warfare - especially civil warfare, waged within a society. But does it tell us anything more than this?
Once again it is an illustration of the way in which both sides in the Syrian conflict are seeking to use social media to publicise their own actions or to castigate those of their opponents.
The individual involved - Abu Sakkar - is the leader of a group of fighters known as the Independent Omar al-Farouq Brigade. ("Brigade" in Syrian terms is an often-used title which does not necessarily denote the size of the formation).
The Farouq Brigade appears to be actually a complex of sub-units with a tangled pedigree, emerging early in the Syrian civil war from the Homs area.
They are seen by Western analysts as being "moderately Islamist", perhaps playing up their religious credentials to attract financial support from the Gulf.
But this gruesome episode is also a powerful reminder of the bitterness and increasingly sectarian nature of the fighting in Syria.
It also highlights - in stark terms - some of the problems facing those Western powers eager to support the opposition.
The Farouq Brigades are a well-established element of the Free Syrian Army - the main grouping of rebel fighters backed by the West.
But the longer the fighting goes on, so the diversity and heterogeneity of the opposition becomes clearer.
Western policy has been to try to push the opposition leadership to coalesce; to extend clear lines of authority over their fighters; and to begin to look more like a government-in-waiting. To an extent this has happened, but progress has dismayed many Western capitals.
This episode then makes the case for Western support of the rebels that much harder. There are already deep concerns that some of the most effective elements of the rebel forces are jihadist groups whose wider goals are antithetical to the West and indeed to many of the opposition's supporters in the Gulf.
The timing of this incident may be significant too. There is a sense that something may be changing in the conflict.
Government forces have been doing better over recent weeks, recapturing territory and re-opening key supply routes.
The dangers of a wider spill-over of the crisis have also increased with bombings in Turkey, Israeli air strikes on alleged weapons supplies going from the Syrian regime to Hezbollah, and a growing role for Lebanese Hezbollah fighters in the fighting.
Amidst still unsubstantiated reports of the use of chemical weapons inside Syria, it is a moment when some key governments in the West are trying to clarify their approach and push for a more active engagement on the side of the rebels.
A man ripping the heart out of a dead opponent - isolated episode or not - makes this task much harder.