Henry Kissinger, no stranger to realpolitik, seems to think that we should take Putin's counterproposal to Bush's proposed missile defense system seriously. I don't agree, because he assumes that Putin could see the long-term benefit of strategic cooperation between the US and Russia.
So far, all I've seen from Putin is posturing in the opposite direction, trying--as Kissinger says it need not do--to position itself as a superior--or at least equal--power to the US. Putin seems far too fond of the Soviet era to ever join in an effort that would stand in the way of what he seems to want to most--Russia's re-emergence as a superpower.
But, if you want to read the other side of the issue, read the story.