Edward Snowden says he does not expect a pardon from US President Barack Obama which would spare the fugitive whistleblower from a toughened approach when Donald Trump takes power.
"I'm not counting on it," Snowden said in an interview published by Yahoo News on Monday.
The former National Security Agency contractor leaked thousands of classified documents to the press in 2013 which revealed the vast scope of US surveillance of private data that was put in place after the 9/11 attacks.
After fleeing his home in Hawaii, he now lives in exile in Russia where he has sought asylum.
Should he ever return to the United States, Snowden would be tried for espionage and other charges carrying up to 30 years in prison.
Since September, there has been a campaign calling for a presidential pardon that has won support from figures such as financier George Soros and Twitter CEO Jack Dorsey.
The campaign says Snowden should be welcomed home "as a hero" for actions that benefited the public because they reined in US surveillance programs and led to improved privacy protection laws.
Snowden's lawyers are trying to win him clemency before Obama leaves office in January or a plea bargain that would shield him from spending a lot of time in jail.
During the election campaign, Trump said of Snowden, "I think he's a total traitor and I would deal with him harshly."
Snowden has repeatedly said he would be prepared to return to the US if he is allowed to address a jury and tell them why he did it.
But that is denied him under the restrictions of the Espionage Act under which he is charged.
Asked in the interview, which was conducted by veteran US newscaster Katie Couric, what he would say to Obama, Snowden admitted his case put the president in a difficult position.
But he said he was heartened by remarks in which Obama said Snowden had performed a public service by starting a debate on US surveillance practices.
"There's one thing that I would hope he understands. And I think based on his recent statements, he does. He said that my actions, and this journalism, raised legitimate concerns," Snowden said.
Journalism is under threat, and people in government who know what is going on -- "particularly when the operations of government start to go out of bounds" -- are more important than ever, he added.
"When something goes wrong, don't we want somebody to stand up and say something about it?" Snowden said.