But the US has reiterated its call for him to face charges over allegations that he tried to sell an arsenal of Soviet-made weaponry to the Revolutionary Armed Forces of Colombia (FARC) guerrillas. Colombia has joined the Obama administration in urging Bout's extradition.
"Just because the cold war is over doesn't mean the competition between military-industrial interests has ended," says Sergei Markov, a pro-Kremlin deputy of the Russian State Duma. "It's not about ideology, but it is about competing interests. Russia extends official support to Bout because he's a citizen, and because the Russian public doesn't see him as any kind of criminal," he says. "They expect him to be supported."
Russia's Foreign Ministry has assisted Mr. Bout and his family, but has had little to say about the case against him, other than to describe the US charges as "unproven."
Mr. Bout, handed lurid nicknames like "Merchant of Death" and "Lord of War" by Western commentators, was arrested in Bangkok in March 2008 after apparently falling for an elaborate sting operation in which agents of the US Drug Enforcement Administration posed as representatives of FARC, which is listed as a terrorist group by the US Department of Justice.
Bout, a former Soviet Army translator, is widely suspected of being a key player in the shadowy arms-smuggling conduits through which corrupt Russian officials and military officers sold off Soviet-era arms stockpiles during the 1990s to warring parties in Africa, the former Yugoslavia, and Asia.
On his own official English-language website, Bout is described as an honest businessman – never an arms dealer – who has been victimized by "fictitious tales and stories" peddled by his rivals.
Viktor Baranets, a leading Russian military expert who has interviewed Bout, says there probably is something "slippery" about Bout's business résumé, but that it will be very difficult to prove anything.
"There are no charges against Bout here in Russia, and Russian Interpol tells me he is not wanted by them," says Mr. Baranets. "The majority of Russians think a Russian citizen should be proven guilty before we accept his arrest. If there's no evidence, and he was simply entrapped, then why should we agree he be sent to the US?"
A Thai court dropped all criminal charges against Bout in August and ruled that he should not be extradited to the US largely on the reasoning that FARC is not a terrorist group. On Thursday, a senior Thai prosecutor said that the country would resist pressure from Washington.
"Every country's justice system is sovereign, and no one can interfere or pressure the judges," Sirisak Tiyapan, executive director of international affairs at the Thai Attorney-General's Office, told news agencies. "This case is under deliberation by the Court of Appeal. To extradite or not is up to the court."
US President Barack Obama has said he will press for Bout's extradition during his trip to Asia next month, and US Deputy Attorney General David Ogden said last week that bringing Bout to trial in an American court is "a matter of great importance to the United States." Colombia filed a long document with the Thai court, outlining 607 reasons why it believes FARC is a terrorist group and urging Bout's extradition to the US.
Bout allegedly agreed to sell millions of dollars in sophisticated weaponry, including anti-aircraft missiles and armor-piercing rockets, to what he thought were FARC representatives.
The Federation of American Scientists has posted copies of documents it says are key elements of the evidence against Bout, including confidential e-mails from Bout's gmail account, handwritten notes by Bout on the weaponry he was offering for sale, a map showing how to avoid US radar stations that cover South American airspace, and details of the Russian cargo aircraft that Bout allegedly intended to use for deliveries.
"I know the US has collected lots of documents against Bout, but legal proof is another thing altogether. When I met with Bout [recently], he categorically denied everything," says Baranets. "He's a slippery fish, and it seems he has guaranteed all his operations in the legal sense so well that the world's best courts will never be able to nail him down."