The New Yorker has an interesting article by David Remnick on the Khodorkovsky trial. Remnick asks whether president Medvedev would be able to pardon Khodorkovsky. Here is the last paragraph:
The Khodorkovsky affair long ago erased any notion in Russia of an independent judiciary; it made plain that the courts do the bidding of a corrupt hierarchy that will stop at little to enrich itself. Khodorkovsky and his lawyers call themselves “realists.” They understand that, although President Obama has raised the issue with Putin, the United States has other pressing business with Russia: nuclear-arms control, North Korea, Afghanistan, Iran. But Russia undermines its pretense to modern statehood with such an appalling abuse of state power. Putin’s ruthlessness is apparent. President Dmitry Medvedev ostensibly has the power to pardon, and he has shown some small measure of independence from his patron, speaking of the “legal nihilism” that prevails in Russia today. Does he have the capacity, much less the courage, to release Mikhail Khodorkovsky?
Short answer: Medvedev does not have tha capacity to release Khodorkovsky if Putin is against it - and he is.