Yes very narrow, and as Lebanon is a Hezboullah stronghold allied to Iran who want Assad to survive, that could cause trouble and even provide MANPADS. If you have SLCMs coasting in over Syrian/Lebenon coastline the ISDAF are going to get very twitchy about their eventual destination, in particular if you are targeting CBRN facilities. As you are well aware SLCMs are only really usable against fixed targets and with no real time data from assets such as E8 Sentinal E3D etc you have a problem, the U2 may provide this data but if permission to use Akrotiri is withdrawn then where do you deploy from?
With the continued draw down of US forces and reduction in combat readiness, could the USAF deploy forces in a short period of time in particular tanker ISAR C4int and strike capacity.