I personally think that Russia made a good decision in flexing some of it's military muscle.  You have to remember... Russia is dealing with China to the south and North Korea to the East.
Both of which have some of the largest, and advanced organized militaries in the world.  China's industry has been funding nationalist sponsored programs like the military for years now, making it the largest in the world.
...Now I'm not saying that China has the strongest... but with 2,255,000 active troops, they are a damn powerful opponent.  Russia has a decent right to be concerned.
The US has bigger fish to fry than worrying about an intercontinental ballistic missile defense system.