The one thing I learned while being a "cold war" sailor is that Russians (and past Soviets) actually care about there children. That's why MAD worked so well. The Islamists live to die and take their women and children with them. If Russia can stall the 7th century madness of 21st high-tech ability, I say let them, so as not on our dime.
If given open season, I believe Russia will put Iran down, commerce or not. As for China, they won't align with Russia to attack the US, we owe them too much. That's a paranoid falsehood. The world is too economically entertwined. It's all chess, and I see Russia about to check the middle east. Better they die, then our children.
And if Russia or China gets too uppity and powerful, here is a warm thought for you...always think Trident! They are out there an no one knows where, unless Obama wants to "leak" their locations, but then they simply move according the Joint Chiefs. They alone could blow much of the world away. MAD is still the best game in town except for Islamist crazies. Again, let Russia deal with them. I don't want to see one more coffin or prosthetics on our children.
Do you truly think we owe the Chinese so much that the possibility of obtaining all US natural resources through an attack is off the table. We have so many assets that I cannot imagine Russia and China not considering it. Seems to be a ripe time to attempt to conquer America... We are divided, broke, militarily weakened. I think our natural resources AND making yourself top global dog, far outweigh any debts we owe China. Russia, China and Iran are not certainly sitting around the table simply discussing Syria.
I agree with you, assuming that the Russians will stay neatly in that box you describe. IMHO eventually they will control almost all of Europes energy resources and start pulling those chains, which is what this is ALL really about( that is not in the box you described).
Russia has indeed always wanted that north/south Iranian rail line. Remember how we used it during WW II to supply the backside of Russia with trucks, aluminum, etc.? I don’t see the downside of Putin explaining to the Mullahs that they’d be running the railroad for awhile.