After leaking details of a classified surveillance program and briefly stopping over in Hong Kong, former NSA contractor Edward Snowden has been hanging out in a transit zone at Sheremetyevo International Airport in Moscow. Russian President Vladimir Putin has stated that he will not be extradited, citing the absence of an extradition treaty and the fact that Snowden has not committed any crime in Russia.

As President Obama pointed out in a statement, no bilateral treaty is necessary for Snowden’s extradition if Moscow really wishes to cooperate. Furthermore, the Russian government requires a transit visa for layovers exceeding 24 hours. Unless Snowden has somehow acquired this document, he technically should have been expelled from Russia already.

The Snowden affair is just the newest link in a lengthy chain of extradition controversies between the two countries. At times, Russia has maintained the upper hand thanks to its constitutional provision that Russian citizens cannot be extradited to foreign states. This provision gave Moscow a convenient reason to refuse the extradition of Andrei Lugovoi, accused of poisoning former FSB agent Alexander Litvinenko, to Great Britain.

This particular stipulation has also frustrated the U.S. on several occasions. There are a number of Russian organized crime ringleaders who face charges in the U.S., but Moscow has never expressed willingness to hand them over. Alimzhan Tokhtakhounov, a native of Tashkent who has Russian citizenship, is wanted on several charges, including money laundering, bribery, and fixing skating matches at the 2002 Salt Lake City Olympics. He reportedly lives a comfortable life in Moscow.

Semion Mogilevich is another crime boss who landed on the FBI’s Ten Most Wanted Fugitives after a 1998 money laundering scheme that defrauded investors of millions of dollars. In 2010, he was arrested in Moscow in connection with a tax evasion case, masquerading as “Sergei Schnaider.” A Moscow court ruled that there was a lack of evidence in the case, and Mogilevich was released.

Decisions such as these have lead to skepticism about the independence of the Russian legal system. This partially explains the tendency of the U.S. to request that third parties extradite wanted Russian criminals. The most noteworthy example is Viktor Bout, a Russian arms dealer whose known customers included warlords and governments throughout Africa. Bout was apprehended in Thailand with the help of the DEA in 2008, which set off intensive lobbying by Russia and the U.S. to have him extradited. The U.S. was ultimately successful, and Bout is now serving a 25-year sentence at an Illinois federal prison. Russian officials have repeatedly denounced his extradition as unfair. More recently, Switzerland extradited Vladimir Zdorovenin to the U.S. in 2012 on cybercrime charges, also amid protests from Moscow.

Considering these clashes, it is doubtful that American diplomats and law enforcement officials will be able to successfully appeal to their Russian counterparts for Snowden’s extradition.  Some Russian politicians have gone so far as to say that Snowden should be granted asylum in Russia. Putin’s previous statements indicate that such a development is unlikely, but housing Snowden in a transit zone and refusing to turn him over presents a golden opportunity to “get back” at the U.S. for these recent extraditions. It’s unlikely that Russia will pass this chance up.