Good points Lobster. and I think both Russia and China deep in their heart wants an Iranian-American confrantation. economic wise they might lose a strong ally in the ME, BUT in terms of geopolitics they will win big time.
Russians and Chinese know Iran will never lose.for the past 5000 years persian empire been statding there. persians survived Romans, Greeks, Arabs, Ottomons, Mongol invasion, even Brits couldnt invade Iran in 20s.
at this point imo US has two choices either learn how to live with nuclear Iran OR try talking to them.