In an interview with the Washington Post just before Christmas, Edward Snowden declared his mission accomplished. At first sight it seemed a grandiose, even hubristic, statement. In fact, it betrayed a kind of modesty about the intentions of the former NSA analyst. "I didn't want to change society," he explained. "I wanted to give society a chance to determine if it should change itself."

Mr Snowden – through journalists, in the absence of meaningful, reliable democratic oversight – had given people enough knowledge about the nature of modern intelligence-gathering to allow an informed debate. Voters might, in fact, decide they were prepared to put privacy above security – but at least they could make that choice on the basis of information.

That debate is now actively happening. In a remarkable week before Christmas, a US judge found that the "almost Orwellian" techniques revealed by Mr Snowden were probably unconstitutional. A review panel of security experts convened by President Obama himself made more than 40 recommendations for change. The leaders of the eight major US tech companies met the president to express their alarm. Parliamentarians, presidents, digital engineers, academics, lawyers and civil rights activists around the world have begun a wide-ranging and intense discussion. Even the more reasonable western security chiefs acknowledge a debate was necessary.

Man does civic duty, and is warmly thanked? Of course not. Should Mr Snowden return to his homeland he can confidently expect to be prosecuted under the Espionage Act and, if convicted – like Chelsea Manning before him – locked away for a very long time. For all his background in constitutional law and human rights, Mr Obama has shown little patience for whistleblowers: his administration has used the Espionage Act against leakers of classified information far more than any of his predecessors. It is difficult to imagine Mr Obama giving Mr Snowden the pardon he deserves. There has been some talk of an amnesty – with NSA officials reportedly prepared to consider a deal allowing Mr Snowden to return to the US in exchange for any documents to which he may still have access. The former head of MI5, Dame Eliza Manningham-Buller recently predicted such an outcome, though Mr Obama's own security adviser, Susan Rice, thought he didn't "deserve" it. A former CIA director, James Woolsey, suggested he "should be hanged by his neck until he is dead".

The first world war vintage Espionage Act is, like its British counterpart, the Official Secrets Act, a clumsy and crude law to use against government officials communicating with journalists on matters where there is a clear public interest – if only because it does not allow a defendant to argue such a public interest in court. It is at least possible that, should he ever face trial, there could be a "jury nullification", where a defendant's peers acquit him even though technically guilty – as in the UK in the 1985 case of Clive Ponting, a civil servant who leaked defence information. Such an outcome would be a humiliating rebuke to those bringing a prosecution.

Mr Snowden gave classified information to journalists, even though he knew the likely consequences. That was an act of some moral courage. Presidents – from Franklin Roosevelt to Ronald Reagan – have issued pardons. The debate that Mr Snowden has facilitated will no doubt be argued over in the US supreme court. If those justices agree with Mr Obama's own review panel and Judge Richard Leon in finding that Mr Snowden did, indeed, raise serious matters of public importance which were previously hidden (or, worse, dishonestly concealed), is it then conceivable that he could be treated as a traitor or common felon? We hope that calm heads within the present administration are working on a strategy to allow Mr Snowden to return to the US with dignity, and the president to use his executive powers to treat him humanely and in a manner that would be a shining example about the value of whistleblowers and of free speech itself.