It’s absurd to describe US-Russian consultations as an “alliance” — good for Trump admin. to engage in sensible military coordination with Russia, but this is far from an “alliance”..... and we should not for a moment imagine that Russia is abandoning support for Iran. They will get what they can from working with the USA but they aren’t going to drop military sales to Iran or ignore their interests when served by working with Iran.
The things that we really really don’t want Iran to do ( like having nuclear weapons with range to Tel Aviv, Berlin and Moscow)
Russia really really doesnt want Iran to do, either
Selling them weapons is one thing
Even protecting the mad mullahs so no one can take them out unless it is at a time and place of Russia’s choosing, if necessary
But making Iran capable of becoming an independent strategic nuclear rogue state?
Not in any major power interest