Illustrations by Laurent Cilluffo. Animation by Alex Purcell

After an eventful six months, Edward Snowden will be hoping for a quieter time ahead – but not as quiet as life in a maximum-security American jail. In Russia since fleeing Hong Kong in June, the NSA computer specialist-turned-whistleblower is living under fairly restrictive conditions. But at least he still has access to the internet – crucial to him – although the Russian president, Vladimir Putin, made it a condition of granting Snowden temporary asylum that he do nothing to embarrass the US further.

Snowden has said he no longer has the documents he leaked, having passed all of them to the journalists he met in Hong Kong in June.

On 21 June, his 30th birthday, the US indicted him on three charges, including two under the Espionage Act: theft of government property, unauthorised communication of national defence information and wilful communication of classified intelligence to an unauthorised person, with a possible combined sentence of up to 30 years in jail. Further charges could be added. The death penalty is also available under a section of the act but the US attorney general, Eric Holder, said in July that Snowden would not face execution.

America would "do everything in its power short of snatching him from Russia to try to have Edward Snowden put on trial in the US", said Elizabeth Goitein, co-director of the Brennan Centre's liberty and national security programme at New York University law school. If he was to try to move somewhere other than Russia, the US would go to great lengths to intercept him, she said.

Goitein, who has worked on government secrecy and privacy rights while serving as counsel to the Democratic senator Russ Feingold, the chairman of the constitution subcommittee of the Senate judiciary committee, predicted that if Snowden were to go on trial in the US, conviction and a long sentence were likely: "I do not think they would settle for a few years in the case of Edward Snowden. [He] is likely to face some very significant jail time."

What are his chances in front of a jury? "Most Americans see him as a whistleblower but many do see him as a traitor. So he would be really rolling the dice," Goitein said.

In the past, whistleblowers have tended to be treated leniently. The most famous in recent American history, Daniel Ellsberg, who in 1971 leaked the Pentagon papers that revealed the US government had misled Congress and the public about its activities in Vietnam, was also charged under the Espionage Act but had all charges dismissed.

In 2011, a former NSA executive, Thomas Drake, faced serious charges but they were dropped on the eve of the trial and he was sentenced to a year's probation and community service.

But the Obama administration is becoming tougher, with former soldier Chelsea Manning sentenced this year to 35 years over the WikiLeaks cables. Goitein said Manning's conviction changed the legal landscape. "The Espionage Act has been used only a handful of times to try to prosecute leaks to the media, and until recently, the effort hasn't been very successful. That's why the verdict and 35-year sentence in Manning's case was such a breakthrough for the government."

Under Obama, there have been seven prosecutions, some of which are still under way. Jennifer Elsea, a lawyer at the independent Congressional Research Service, wrote in a recent report: "A number of other cases involving charges under the Espionage Act, including efforts to extradite Edward Snowden, demonstrate the Obama administration's relatively hardline policy with respect to the prosecution of persons suspected of leaking classified information to the media."

There is almost no legal protection for whistleblowers disclosing misconduct or abuse.

Like Goitein, Dinah PoKempner, general counsel of Human Rights Watch, is pessimistic about Snowden's chances in a US court. "While there is little doubt that Edward Snowden would have highly credible claims under international human rights standards for protection as a whistleblower, US law offers no protection for those who reveal to the public wrongdoing in the areas of national security or intelligence," she said. "His rights would not be protected, and he would not be able to count on this as a defence to criminal charges."

Snowden has permission to live, work and travel in Russia until 31 July next year, although he is likely to be granted further extensions beyond that. His supporters in Germany, including prominent members of the Green party, are pushing for him to be granted asylum in the country, given the service they say he has done in revealing the scale of surveillance, particularly the secret US monitoring of Angela Merkel's mobile phone. But the German government has made it clear that this is an unlikely as it does not view him as a political refugee.

One of the worst-case scenarios for Snowden is if Russia, after a few years of exploiting his presence for propaganda purposes, decided to do a deal with the US, possibly exchanging him for a high-profile Russian in an American jail.