Ivan, when did the U.S. ever oppose Russia building the exact same missile shield?==
You true. Nothing. But the inbalance created by new shield exists right? Try to put yourself on place of Russia. What did you feel if it was Russia who installed new shield right now?
My FRiend, if Russia had decided to just build the shield without telling anyone about it, I would be worried. But, if Russia decided to do the following...
1. Share the shield with several other countries.
2. Offer America and NATO the technology to build a shield of our own (as we offered it to them)
3. Concentrate the shield in parts of their territory that Iran could attack while leaving other parts vulnerable to NATO or Chinese attack (in the same way America is giving the shield first to Israel and to the NATO countries that can be hit with an Iranian missile)
...then I would not feel threatened at all.
So why does Russia?
To use the bulletproof vest analogy, let's say my neighbor and I both have shotguns. He buys a bullet proof vest and says, "I'm worried that guy at the end of the street might shot at us both. Here's a bulletproof vest so he can't hit you." I turn it down. After that conversation, should I see his vest as a sign that he is preparing to kill me with his shotgun?