Russia is in it to gain influence and cultivate a client state - and tease the west.
Putin wants to return Russia to its status of 1983 when it was a world superpower, not 1943 when it was a war ravaged derelict.
But If it actually ever came down to war with Iran tht could possible expand on to Russian soil I believe Putin would throw Iran under the bus without a second thought.
Of course, how far he would go before doing that would be determined by any number of things, including who the American President was at the time.
If it was Obama, drawing another Red Line, Putin would probably go to the wall. If it was Ted Cruz he would bail out much earlier.
likely, unfortunately since bambi occupies 1600 penn ave the next few years are going to be rough. I’d love to the the wanker running for potus to state if the s-300’s get shipped to iran, we’re going to pay big oils fracking bills, and gift offensive and defensive missile systems to the Baltic states, Georgia, Ukraine, Saudis etc. Then get the DC elected wankers to terminate any bank/country that does business with Iran, access to the US clearance system and any business working with those countries any access to the us banking system. Even China would stop the crap.