Julian Borger, The Guardian:
Russian military advisers are manning some of Syria’s more sophisticated air defences – something that would complicate any future US-led intervention, the Guardian has learned.
The advisers have been deployed with new surface-to-air systems and upgrades of old systems, which Moscow has supplied to the Assad regime since the Syrian revolution broke out 21 months ago.
The depth and complexity of Syria’s anti-aircraft defences mean that any direct western campaign, in support of a no-fly zone or in the form of punitive air strikes against the leadership, would be costly, protracted and risky.
…
Air strikes against chemical weapon depots would potentially disperse lethal gases over a vast area, triggering a humanitarian disaster. US and allied special forces have been trained to seize the air bases where the warheads are kept, but it is unclear what the next step would be. It would be physically impossible to fly the hundreds of warheads out of the country, while it would take thousands of troops to guard the arsenal for what could be many months.