Is it possible Russia’s REAL objective here is to establish a reaction force in defense of Iran in response to Israel’s inevitable attack on Iran???
So really, our administration is just mad because the Russians are doing it first. We would be expected to defend Iran against Israel according to the 'IRAN DEAL'.
The Syrian government is the last Russian/Soviet client state left in the Middle East and it has been reduced to a rump state with little control of its territory.
The Russians are trying to prop up one of their last best customers for their crappy weapon systems.