I still haven’t heard a completely satisfactory answer to this question, but Stephen Sestanovich at CFR is getting warmer.
As the killing in Kyrgyzstan escalated, some American analysts feared that Moscow saw disorder there as a chance to throw its weight around in its own neighborhood. There can be little doubt that Russia wants to create a sphere of influence, but in this case that goal was better advanced by passivity than by activism. Intervening in Kyrgyzstan would, as a practical matter, have required a great deal of international coordination and approval. And that–above all, when the states of the former Soviet Union are involved–is something Russian policymakers still have trouble with.
It’s for this reason–limiting the role of outsiders, whatever the human cost–that Russia has long blocked efforts to expand the peacekeeping role of the Organization for Security and Cooperation in Europe (OSCE). For years it has professed support for the U.S. military campaign in Afghanistan, but without ever supporting its obvious prerequisite, U.S. access to Central Asian airbases. (Just last week, Medvedev repeated that use of the airfield in Manas must not continue indefinitely.) Given this record, it was no surprise that Russian diplomats also dragged their feet in letting the UN Security Council even issue statements on events in Kyrgyzstan.