Days after Kucherena joined a group of Russian public figures at a surreal meeting in the international transit lounge of Sheremetyevo airport on July 12, Snowden asked him to take up his case for political asylum. And he agreed, pro bono.

That has made him the architect of Snowden's effort to stay in Russia, and effectively his unexpected public champion.

Since he is one of the few people who get to meet Snowden, he has been besieged for updates in the proceedings and also for hints about his client's strategy and mood as his odyssey unfolds.

"He has this struggle inside himself," Kucherena said the other day in a restaurant near the Kremlin that he has turned into an unofficial office.

Kucherena's role has increased his prominence in Russia. Like many defence lawyers in a country where justice is viewed as deeply politicised, he occupies an awkward space between challenging authority and being part of the system itself.

At the same time, he is a political supporter of Putin's and serves on the Public Chamber, an advisory body. He also serves as a member of another board that oversees the Federal Security Service, or FSB.

Those roles have prompted accusations that the Kremlin is orchestrating events and that Kucherena has ties to the authorities or the security service itself, which he disputed.

It was Kucherena who counselled Snowden to abandon his appeals for political asylum in more than 20 other countries, arguing that they had no legal standing while he remained on Russian soil.

Instead he helped Snowden file the request for a form of temporary refuge in Russia to avoid a drawn-out review that would ultimately end up on the desk of President Vladimir Putin. He said statements by the US State Department and members of Congress had bolstered his case for asylum. That was despite a letter from Attorney General Eric Holder to his Russian counterpart promising Snowden would receive a fair trial and disputing Snowden's assertions he faced torture or the death penalty if he returned to the US.

"This is in the realm of big politics," Kucherena said. He added, though, that Snowden's appeal was a purely legal matter that would prevail on the merits.

"I am a lawyer. I don't want to be involved in big politics," he added.

Only Snowden knows why he settled on Kucherena to represent him. But he was one of two lawyers who attended the airport meeting along with representatives of advocacy groups like Amnesty International and Human Rights Watch.

Snowden selected those who attended from a list drafted at his request by officials from the border police who control access to the transit lounge. Tanya Lokshina of Human Rights Watch, who also attended, described Kucherena as a capable lawyer who also remained a "staunch loyalist" of the Kremlin.

Kucherena has previously dealt with US extradition requests. He represented Alimzhan Tokhtakhounov, the reputed mafia boss known as Taiwanchik, who the US has been pursuing on a variety of charges since it first accused him of fixing figure-skating events at the Olympics in Salt Lake City in 2002.

Tokhtakhounov, who lives in Moscow and denies the accusations, said Kucherena defended him well. "He's a big guy, but he's also an ordinary lawyer," he said. "You pay him money and he will defend you."

As for Snowden, Tokhtakhounov offered advice from his own experience: "It's horrible to live on the wanted list."