Among the writers in the Guardian are Daniel Ellsberg, the whistleblower who released the Pentagon Papers in the 1970s, who calls for Snowden to be allowed to make a public interest defense in any US trial. From the world of arts, actor Susan Sarandon and director Terry Gilliam, novelist Barry Eisler and Sonic Youth singer Thurston Moore all make impassioned calls for an Obama pardon.

Senior politicians from both sides of the Atlantic, including former US senator Mark Udall, UK parliamentarian David Winnick and German Green party member Hans-Christian Ströbele all fly the flag for a Snowden homecoming. Similar calls are made by public intellectuals including Noam Chomsky, Cornel West and Sanders’ former Democratic presidential rival and Harvard law professor, Lawrence Lessig.

Daniel Ellsberg

Former US military analyst who released the 1971 Pentagon Papers on the Vietnam war, and who met Snowden in Moscow last year

 Daniel Ellsberg: ‘As things stand, I think the chance that this or any president will pardon Snowden is zero.’ Photograph: Stephen Hird/Reuters

Ed Snowden should be freed of the legal burden hanging over him. They should remove the indictment, pardon him if that’s the way to do it, so that he is no longer facing prison.

The NSA and US government have revealed no evidence that the information Ed Snowden released has caused any harm. Inconvenience, yes, embarrassment certainly, but what has truly been revealed is that the NSA itself was unquestionably committing international, domestic and constitutional crimes.

Were the government to have any evidence that Snowden revealed information that should have been protected, I think he should be judged by a jury. I was the first person to be tried for a leak under the Espionage Act, and I certainly didn’t object to my case being weighed by a jury, although it never came to that. But there has to be a public interest defense, which doesn’t exist in US law now.

As things stand, I think the chance that this or any president will pardon Snowden is zero. They wouldn’t dare to challenge the intelligence community that remains so hostile to him. Nor does Snowden have any chance of a fair trial under the Espionage Act, any more than I did.

So nothing would be gained by him coming back and standing trial unless the Espionage Act were changed to permit that public interest defense. He’s said to me that he’s willing to come back and serve one, two or conceivably three years as a result of a plea bargain arranged beforehand, but they haven’t offered him one as far as I’m aware.   *************

Noam Chomsky said: Snowden should, in my opinion, be welcomed home with honors for his service to his country, and for his courage and integrity in the manner in which he performed this service. Apart from exceptional circumstances, citizens have every right to know what their government is doing, in particular what it is doing to them – in the present case, as Snowden revealed to us, keeping citizens under extensive and deeply intrusive surveillance.

No case has been made that relevant exceptional circumstances prevail. As well known, initial claims about prevention of terrorist actions collapsed under investigation, and no credible case has been made that the massive invasion of privacy, arguably in violation of constitutional rights, is warranted. Snowden made every effort to follow established procedures for bringing this crucial information to the general public. When these failed, he took the courageous and honorable step of transmitting the information through the medium of careful and highly reliable and experienced journalists, who, along with him, carefully vetted the material to ensure that no possible harm would be caused to individuals or to security.

Citizens of the United States – and indeed the world, considering the extraordinary range of the operations that have been revealed – are very much in Snowden’s debt. He should certainly not be punished in any way for the services that he has performed in the interests of democracy and civil rights. At the very least, he should be granted the full freedom to return home without fear of prosecution, and, I very much hope, to be welcomed with the respect that he richly deserves.********

Barry Eisler

Bestselling novelist and former covert CIA operative

Barry Eisler, a former tech attorney who parlayed three years as a covert CIA operative into novels. Photograph: Sacramento Bee/MCT via Getty Images

I wholeheartedly support a full presidential pardon for whistleblower Edward Snowden.

As a CIA officer 25 years ago, I knew the government classified too much information. Everyone knew it. But no one spoke up. And today the problem is far worse.

For his service to his country, he deserves a Presidential Medal of Freedom.

But because of Edward Snowden, we now know the head of US intelligence was lying to the Senate committee responsible for intelligence oversight. Programs concealed from the citizenry have been declared unconstitutional by federal courts. For the first time, the country has the minimal information necessary to grapple with the benefits and dangers of a surveillance apparatus far more vast and intrusive even than the one Senator Frank Church warned 40 years ago could lead to the eradication of privacy and the imposition of tyranny.

Surely in a democracy, the people have a right to know about the implementation of programs with risks as vast as that. Surely in a democracy, the people have a need to know.

That today we do know, that today we are able to engage in this critical conversation about how properly to govern ourselves, is almost entirely due to the conscience and courage of one man: Edward Snowden. For his service to his country, he deserves a Presidential Medal of Freedom. But a presidential pardon might be acknowledgment enough.*****************

 Salil Shetty: ‘Punishing him for this sends out the dangerous message that those who witness human rights violations behind closed doors should not speak out.’

‘Edward Snowden clearly acted in the public interest. He sparked one of the most important debates about government surveillance in decades, and brought about a global movement in defence of privacy in the digital age. Punishing him for this sends out the dangerous message that those who witness human rights violations behind closed doors should not speak out.

‘It is ironic that it is Snowden who is being treated like a spy when his act of courage drew attention to the fact that the US and UK governments were illegally spying on millions of people without their consent.*****

 Lawrence Lessig: ‘Whistleblowing is an essential part of the architecture of checking government power.’ Photograph: Brian Snyder/Reuters

“There should be nothing less than a full pardon. The information that Snowden released to the public was critical: it made Americans aware of the way the law was being violated or at least subverted by unchecked government officials.

“Then there was the manner in which he released the information. It was careful and limited, given the unresponsiveness he had experienced inside the NSA and from other branches of government.

“Whistleblowing is an essential part of the architecture of checking government power. We’ve recognized the importance of whistleblowers in the past, and it’s entirely appropriate that Obama now recognizes the role that Snowden played in America in exposing the way in which extraordinary power was abused. *************

 Karen Greenberg.

‘What if there hadn’t been a Snowden? A program that violated the principles that this country holds dear may have continued to this day. A program that an appellate court in New York found illegal, that was so egregious in terms of law and civil liberties, may have continued or even been expanded.

‘Edward Snowden was immensely important and will only become more important as time goes on. Not only did he show the American public what was being done in their name and to them, he ended a program which, upon examination, national security and legal experts concluded did not work.

‘The importance of what he did for the country outweighs the law that he violated

‘When considering whether or not he deserves to be pardoned, the president should remember that even former attorney general Eric Holder said that Snowden performed a public service. His revelations were the tidal wave the nation needed to change its ways. The importance of what he did for the country outweighs the law that he violated and the just move is a pardon for Edward Snowden.