The day before President Obama left office, a US Air Force B-52 bomber struck a training camp used by Jabhat Fatah al-Sham (JFS), the al-Qa'ida affiliate in Syria. The number of casualties varies: the US military put the total at around 100 while others cited lower figures. But as well as JFS, there were also reportedly members of the rebel group Harakat Nur al-Din al-Zinki among the dead.

To most, the deaths of fighters training with JFS would be unremarkable. But the presence of al-Zinki Movement fighters at the JFS camp is a good illustration (if any were needed) as to why Washington and Western governments have found it difficult to craft a coherent Syria policy in the absence of reliable partners on the ground. The al-Zinki movement was previously a vetted, 'moderate' rebel group, supplied with weapons by the US. 

This goes to show the wicked webs we weave when we use imprecise or simplistic language (often because it is touted by lobbyists and/or policy makers) to describe complex situations. Take the rather meaningless terminology about ‘moderate’ rebel groups which were somehow acceptable, and ‘vetted’ rebel groups which were worthy of receiving weapons. The problem, of course, is that the term 'moderate' can be so contested; every armed group that is not Islamic State can be considered moderate in the context of Syria, but can still be radical to the West. Spokespeople never defined what they meant by moderate, nor did many commentators try to define what the term meant.

The same confusion came with the term 'vetted'. For those who have undergone high-level security clearance procedures, being vetted connotes a detailed process that requires months of checks, long interviews and cross-checking. Even then, it is not guaranteed to produce absolute success. The discord between this popular notion of vetting and what passes for it in the Syrian context has at least been recognised, even if it hasn’t stopped the term being used without caveat.

Of course in the world of realpolitik, the US has often ignored the actions of those that it wishes to back (the old ‘our son of bitch’ rule) but the lesson from the Afghan war with the Soviets was that, when dealing with Islamist groups, the long-term dangers of supporting them against a political opponent are likely to be worse than the short-term benefits. The plethora of armed groups in Syria made an already circumspect President Barack Obama even more so. But ultimately it was thought that not engaging at all would have worse consequences than limited engagement, as it would leave the field clear for countries like Turkey and some of the Gulf states to provide support to groups without much regard for centralised control. This is the environment into which President Donald Trump may deploy US troops in establishing his so-called Syrian 'safe zones'. It will be interesting to see what plan his Secretary of Defence comes up with in the event the new President does go down this road.