We already have several show trails going on because of whistle-blowers. We don't need another.

he is a pawn in Putin's game

This is conspiracy talk. Putin "declared that Snowden was free to leave and should do so." Snowden was never interviewed by Russian intelligence agencies, he's never worked with them, and a condition of his asylum is that he doesn't work to affect US-Russian relations. Putin called Snowden "an unwanted Christmas gift."

The only reason he is in Russia because he can't go anywhere else. When there were talks of assylm in Latin America, the United States forced down the plane of Bolivia's president.

Snowden said he remained in Russia because "when we were talking about possibilities for asylum in Latin America, the United States forced down the Bolivian President’s plane", citing the Morales plane incident. On the issue, he said "some governments in Western European and North American states have demonstrated a willingness to act outside the law, and this behavior persists today. This unlawful threat makes it impossible for me to travel to Latin America and enjoy the asylum granted there in accordance with our shared rights." He said that he would travel from Russia if there was no interference from the U.S. government.

You have no basis to call him a pawn in Putin's game. In fact, Putin has done everything he can to distance himself from the "Snowden situation." Putin doesn't want him in Russia, but he's been forced to accept him because otherwise he'll look weak.

On Meet the Press in late January 2014, speculation arose from top U.S. officials in the House and Senate Intelligence Committees that Snowden might have been assisted by Russian intelligence,[298] prompting a rare interview during which Snowden spoke in his defense. He told The New Yorker "this 'Russian spy' push is absurd," adding that he "clearly and unambiguously acted alone, with no assistance from anyone, much less a government."[27] The New York Times reported that investigations by the NSA and the FBI "have turned up no evidence that Mr. Snowden was aided by others."[299] Days later, Feinstein stated that she had seen no evidence that Snowden is a Russian spy.[300] Germany's Der Spiegel suggested the accusations were part of a "smear campaign" by U.S. officials. For Snowden, the smears did not "mystify" him; he said that "outlets report statements that the speakers themselves admit are sheer speculation."