As has been widely reported, Russia has denied the United Kingdom's request for the extradition of Andrei K. Lugovoi, a Russian national who is wanted for the murder of Alexander V. Litvinenko. The legal basis for the British request was the Council of Europe's European Convention on Extradition, as supplemented by its Additional Protocol. And the legal basis for Russia's refusal was Article 6 of the Convention, which states that "A Contracting Party shall have the right to refuse extradition of its nationals." (Article 61(1) of the Russian Constitution prohibits the extradition of Russian nationals, and a declaration attached to Russia's instrument of ratification notes this provision.) Prime Minster Gordon Brown (through his spokesman) described the Russian decision as "extremely disappointing," and he "deeply regret[ted] that Russia has failed to show the necessary level of cooperation in this matter." Brown also rejected Russia's offer to try Lugovoi in Russia, as is permitted under Russian law (and as is recognized by the Convention as a legitimate alternative in the event extradition is refused on the basis of the nationality of the fugitive): "This was a crime that was committed in London, the evidence and the witnesses are in the United Kingdom, and we do not have confidence that a trial in Moscow would meet the standards of impartiality and fairness that we would deem necessary." Apparently, the British are considering retaliatory measures such as the expulsion of Russian diplomats.
Contrary to the heated rhetoric, for those who follow international extradition, the Russian decision is no surprise. Even under the Convention (which entered into force between the two countries in March 2000, following Russia's ratification), there have been no extraditions between Russia and the United Kingdom, even in less politically sensitive cases than this. Indeed, Russia has made at least seventeen extradition requests, including for billionaire political dissident Boris A. Berezovsky, not one of them successful. (This was only the second British request.) Further, in accordance with its Constitution, Russia never extradites its own nationals. As a Russian Foreign Ministry spokesman quipped, the West had "persistently called on Russia to build a state functioning according to the law," so how can the U.K. complain when Russia was complying with its domestic law?
If the Russian response was predictable (and it was), and if the Russian denial was in accord with its international and domestic obligations (and it was), why did the British bother to ask for Lugovoi and why did they make such a fuss when Russia refused? There are at least four possible reasons. First, the British may have felt that they needed to take all steps (no matter how remote) to solve a serious crime within their jurisdiction. They've now checked this box. Second, and relatedly, the British authorities may have been under domestic pressure to take this step, and so they did it despite its evident futility. Third, the Russian denial of Lugovoi's extradition can now be used as a counterpoint by the British any time that Russia complains about the U.K.'s failure to extradite a fugitive (such as Berezovsky) to Russia. And fourth, the British must think that further stirring the Litvinenko pot in this way will be otherwise useful in their bilateral relations with Russia.
UPDATE: A fifth explanation seems just as, if not more, likely: It is thought that Lugovoi's actions on British soil were at the direction of certain components of the Russian Government. The failure to extradite provides the U.K. with the predicate to take action against Moscow itself. A strong British reaction, particularly through expulsion of persons accredited to the Russian Embassy in London, would send a signal of severe displeasure not just with the extradition decision but also (and more importantly) with the underlying act itself and the Russian Government's presumed involvement therein. That is, the British simply will not abide by a foreign government operation like this on its territory.