Who else could have acquired the polonium 210? Who else would kill Litvinenko to make Putin a pariah? These are the questions Scotland Yard, which also seems skeptical that Putin had a hand in this bizarre business, has begun to ask.

As the predictable effect of Litvinenko's death has been to put a cloud of suspicion over Putin and a chill over Russian relations with the West, one must ask: To whose benefit is the discrediting of Putin? Who would seek a renewal of the Cold War?

Certainly, the oligarchs and robber barons like Berezovsky -- many of them now dispossessed of the wealth they amassed in a collapsing Soviet Union, and all of whom have been run out of the country or imprisoned -- have the most powerful of motives. They hate Putin and seek to bring him down. And Goldfarb and Litvinenko both enjoyed the patronage of the billionaire Berezovsky.

Surely, rogue or retired KGB agents, passed over by Putin and bitter at Litvinenko, would have a motive: to send a message, written in polonium 210, that this is what happens to those who betray us and Mother Russia.

Scotland Yard has yet to declare this a murder case and is looking into the possibility of a "martyrdom operation" -- suicide dressed up like murder -- in which Litvinenko may have colluded. The Putin-dominated Russian press is pushing this line, as well as the idea of an oligarchs' plot to discredit Putin and destroy Russia's relations with the West.

Yet Litvinenko was still in his early 40s, with a wife and two children. While his agonizing public death would make him a celebrity even more famous than Georgi Markov, the Bulgarian anti-communist murdered in London in 1979 with a poison-tipped umbrella, Litvinenko would not be around to enjoy his fame.

America has a vital interest in this Scotland Yard investigation. What it discovers may tell us more about the character of the man into whose eyes George Bush claimed to have stared, and seen his soul, or it may tell us who the real enemies of this country are, who are out to restart the Cold War, and perhaps another hot one.