For one, what does the U.S. stand to gain from making a move that will be read in almost all corners of the globe as an indication of weakness?
Does the specific move of eliminating "the third site" in exchange for "greater cooperation on Iran" even make sense? The Obama administration's move, which comes after months of hinting, is very concrete. The item being bartered for is as nebulous as mist. What does greater cooperation on Iran entail? What incentive does Russia have to hold up its part of the ostensible bargain? If Russia gives a little bit on Iran and then refuses to go any farther, what happens next in the relationship?
The short term Russian concession, refraining from deploying missile launchers near Poland, was a hypothetical move to begin with, so there's no loss to Russia whatsoever. Russia bluffed and it cost nothing. And Russia retains the advantage geographically when it comes to deploying force in Eastern Europe.
In the meantime, as Gates notes, no missile defense umbrella covers Europe. While you could argue that the calls in the middle of the night were not as devastatingly short notice as they're painted to be, they still seem shady. All attention seems to focus on Iran as the missile threat, but Russia knows that it just removed one future hurdle to the full potency of its own arsenal, which, like its control over hydrocarbon pipelines, can be used as a foreign affairs tool. Russia has long opposed missile defense because an operational system would stand to render a good deal of its arsenal less meaningful.
Gates and Obama also cited cost as a factor in the decision. While I think Europe should be financing more of its own defense in accordance with my general belief that the U.S. is overextended, I have to wager that even an expensive missile defense shield is arguably worth the cost if it stands to defend crucial allies and the U.S. itself from nuclear devastation.
I know that missile defense systems are not necessarily as easy to classify in a sword versus shield sense in a nuclear calculus, but I think the defensive posture of the system was one thing Obama could have focused on, something that should have put Russia in a far weaker rhetorical position. We're just trying to defend people - and you disagree for some reason? And even beyond that point, this whole matter was never just about missile defense anyway - it was overtly interwoven with a desire for alliance building in a crucial region.
Overall, this is not just about Iran. Or Europe. Or Russia. As Brian Kennedy notes in the Wall Street Journal, it is, in part, about the overarching purpose of defending the U.S.:
With Mr. Obama's Third Site move, the U.S. is not merely abandoning a system to stop long-range Iranian ballistic missiles from hitting Europe but are also foregoing a system to stop Russian or Chinese ballistic missiles from destroying the U.S.
And, what's more, the move sends unwanted signals to Japan, South Korea, and Taiwan as well - countries who find themselves in situations roughly analogous to Eastern European nations.
President Obama clearly has a number of motives for the move in relation to his goals with various international treaties and bodies. But I wonder how many of Obama's moves, based on a hope that other nations will reciprocate or follow suit...will be met with less than promising or fully symmetrical responses.