I found a post over at Jalopnix that has a reason why Russia's intervening in Syria - they, like in Crimea have fleet access to the ports there.
Still, like in the South China Sea near Taiwan, I would not like to be on a non-Russian naval vessel entering, or in, the Black Sea right now, and of cause the USN has parked three vessels in there: USS Mount Whitney (6th Fleet's flagship), USS Taylor (escort of the Whitney, last known to be in a Turkish drydock for propeller repairs from a grounding incident) and now the USS Truxton. I'd expect that there would be a USN submarine or two in there too, but they won't be happy about having to hide in a bathtub.
Still, like in the South China Sea near Taiwan, I would not like to be on a non-Russian naval vessel entering, or in, the Black Sea right now, and of cause the USN has parked three vessels in there: USS Mount Whitney (6th Fleet's flagship), USS Taylor (escort of the Whitney, last known to be in a Turkish drydock for propeller repairs from a grounding incident) and now the USS Truxton. I'd expect that there would be a USN submarine or two in there too, but they won't be happy about having to hide in a bathtub.