Obama in Russia. I'm not sure any gestures made in attempt to 'reset' relations will matter if you don't know who's in charge - and we don't know who's in charge nor what exactly the agreement is between Putin and Medvedev - are they co-conspirators or rivals? is there a trust or mutual suspicion between them? is it possible they themselves are still exploring the limits and boundaries defining the relationship? Common sense would suggest Putin wouldn't have selected Medvedev without an understanding existing but that of course doesn't rule out Medvedev being a cunning bastard with plans of his own - but then again one has to believe Putin would have been very careful to guard against such a thing. There is a limited but still somewhat relevant opposition to Putin in the country and one can't simply dismiss possibility that Medvedev shares some of their concerns - but much more likely that if there is a divide between the two it's because of Medvedev's ambitions to out Putin Putin - I mean, he is a short little bastard and that ilk has a history of not dealing well with the seductions of power.
One thing for sure, the lack of clarity is to the advantage of Russia and disadvantage of the States, something which Putin would be entirely aware of and would explain why no effort is made to make clear who's calling the shots. Thus, any agreements you make under these conditions are of dubious merit and must be carefully calibrated - to wit, nuclear arms reductions. These reductions are all to Russia's advantage since they cannot afford to maintain long range missile capacity as is and the agreement does not address tactical weapons of which Russia has a large numerical edge - so essentially Obama looks to be giving away something for nothing. Obama of course is thinking about the nonproliferation treaty which requires efforts to reduce stockpiles - but if Putin believes that the NPT is a worthless document, no longer relevant [and if Russia helps Iran become a nuclear power he'd have good cause to believe that] then you still have the appearance of America giving away something for nothing.
It's possible that Obama is trying with these agreements and negotiations to separate the sand from the water - Iran would be the sieve - ie, create a situation where Medvedev can diverge from Putin over Iran and thereby throw light on the leadership question. Something like that is possible I suppose, although I have trouble seeing exactly how the math would work. More likely I'm afraid is that this is just further evidence of Obama's vain romanticism in the realm of foreign policy and an extension of his misguided 'world without nukes' agenda.
Of course I haven't considered how European missile defense figures into the equation. Apparently Obama did come out today in a Moscow speech and say that if Iran has no nukes then the missile shield is unnecessary - something of an odd statement since the real targets of the missile shield are of a global nature, including Russia and China, not simply about Iran - but if they are trying to drive a wedge between Medvedev and Putin such a declaration would make sense - probably the only hope left of stopping Iran's nuclear ambitions is to get Russia on board as a hardliner - Obama can't go back now re missile shield logic should Iran acquire the bomb - so in effect they're hanging a big carrot out there for Medvedev - either that or setting the stage for some serious confrontations down the road or an even more serious capitulation by Obama.
One sees now how the murky leadership issue favours Russia - they can intimate a division between Medvedev and Putin, intimate action on Iran and manipulate America, if Obama chooses to embrace an unreasonable optimism regarding these things, into a losing position: no missile shield, arms reductions that entirely favour Russia - and China for that matter - and a proxy in Iran serving anti-Americanism everywhere.
You can't negotiate with people if you don't know what they want.