“The only debate we’re really having in the U.S. is about the very first document that Snowden produced,” said Stewart A. Baker, a former N.S.A. general counsel and outspoken critic of the leaks, referring to the secret court order authorizing the phone records program. “The rest of the documents have been used as a kind of intelligence porn for the rest of the world — ‘Oooh, look at what N.S.A. is doing.’ ”

In a new memoir, Michael J. Morell, former deputy director and acting director of the C.I.A., expresses the dark view of many intelligence veterans, even blaming Mr. Snowden’s leaks for empowering the Islamic State extremist group, also known as ISIS or ISIL.

“ISIS was one of the terrorist groups that learned from Snowden, and it is clear his actions played a role in the rise of ISIS,” Mr. Morell writes in “The Great War of Our Time,” offering no elaboration. “In short, Snowden has made the United States and our allies considerably less safe. I do not say this lightly: Americans may well die at the hands of terrorists because of Edward Snowden’s actions.”

Given such assessments, prosecutors have shown no inclination to offer Mr. Snowden a plea bargain he would accept. The Russian government granted him a three-year residency last summer, and he has no obvious prospect of leaving any time soon. Even if Mr. Snowden acquired some kind of travel documents — the United States has revoked his passport and he is not a citizen of Russia, so he has no Russian passport — he would face a high risk of arrest in any other country and a return to the United States for trial.

Some Russian commentators have remarked on the paradox of Mr. Snowden’s calls for liberty and privacy from President Vladimir V. Putin’s increasingly authoritarian country.

“All these months he’s been pretending successfully he was not in Russia, but just somewhere, in some limbo,” Andrei Soldatov, a journalist who runs an investigative website covering Russian intelligence, said in an email. Mr. Snowden has found asylum, he added, “in a country which is on a crusade against Internet freedoms.”

Mr. Snowden’s main source of income, his lawyer said, is speaking fees, which have sometimes exceeded $10,000 for an appearance. His American girlfriend, Lindsay Mills, who represented him at the Academy Awards ceremony in February, has joined him in Moscow.