As a practical matter, there's nothing Obama can do about it and that's largely not because of Obama's policies but because of the stupidity of Congress (mostly the GOP, but Congress in general) and its pro-Zionist leanings.
Yes, that's correct. If Obama does something to try to deter Russia (sanctions, freezing of assets of high-ranking Russian officials, businessmen), all Russia has to do is turn around and deliver its latest, greatest air-defense systems (S-4) to Iran.
And voila, Congress will back down and retract the freezes, sanctions, etc. because it's soooooooo desperate to do anything at all to coddle the Israeli regime. So the US govt. doesn't really care about international law, invasions, etc.; it really just cares about propping up the aggressive Israeli regime and defending its interests at all costs, and because Putin knows that, he has an ace in the hole--you do anything to me, I'll make Iran's life easier.
And that's the fundamental problem--the reason why the US is seen as weak on the international stage. In the past 50 years, in spite of its bellicose pro-freedom rhetoric, the US govt. has demonstrated by its actions that it doesn't really care about freedom; it just cares about maintaining its oil interests and the Israeli regime at all costs and uses "fighting for freedom, democracy" as a ruse to make its invasions popular among the gullible US public.
