David Irving, the infamous British war historian, is today sitting in an Austrian jail, accused of denying the Nazi Holocaust. So why is an American Jewish academic who dramatically crushed Irving in the British courts saying he should be released?
When you ask Professor Deborah Lipstadt for her thoughts on David Irving's forthcoming trial, the very last thing you expect her to say is: "Let the guy go home. He has spent enough time in prison."
Lipstadt, the American Jewish academic who exposes Holocaust deniers is not exactly David Irving's greatest fan.
But five years after she famously defended her own reputation in the High Court, and in doing so shredded Irving's, she is arguing that the Austrian authorities should probably let him go, saying the far-right will find a martyr if he goes to jail.
David Irving, 67, who made his name as a World War II historian, became infamous for suggesting that the Holocaust didn't happen.
But in November last year he was arrested in Austria for two speeches he made in 1989, during which he allegedly claimed there had been no gas chambers at Auschwitz.
It is a crime in Austria to minimise the atrocities of the Third Reich and the historian faces up to 10 years imprisonment if found guilty. Speaking after the arrest, Irving's lawyer said the historian no longer denies that gas chambers existed in Nazi death camps.
Yet Lipstadt, arguably the best-known warrior against Holocaust denial, believes that the best outcome would be for Irving to be let go.
"I would not want to see him spend more time in jail," she says.
"I am uncomfortable with imprisoning people for speech. Let him go and let him fade from everyone's radar screens."
If there were to be a film of Deborah Lipstadt and David Irving, they would be presented as nothing less than arch enemies, fighting to the last - as they indeed did in the High Court.
Irving said his reputation as an historian had been 'vandalised'
Lipstadt has spent years exposing the arguments of Nazi sympathisers. She warns historians must "remain ever vigilant" against those who say the Holocaust was a hoax, "so that the precious tools of our trade and our society - truth and reason - can prevail".
The showdown came in January 2000 when she stood accused of libel for describing Irving in a book as "one of the most dangerous spokespersons for Holocaust denial"; he accused her of "vandalising" his legitimacy as an historian.
The 32-day trial became a legal debate on the history of the Nazis - and the nature of truth itself.
Mr Justice Gray witheringly described Irving as anti-Semitic, racist and a Holocaust denier who had "deliberately misrepresented and manipulated historical evidence".
Irving had comprehensively lost not just his money, but his reputation.
Much to the annoyance of those who have fought against him, Irving is still invited to speak both in Europe and the USA. And Lipstadt raises questions about both free speech, and the publicity Irving stands to gain at his impending trial.
"Generally, I don't think Holocaust denial should be a crime," she says. "I am a free speech person, I am against censorship."
"I don't find these laws efficacious. I think they turn Holocaust denial into forbidden fruit, and make it more attractive to people who want to toy with the system or challenge the system.
"We don't have laws against other kinds of spoken craziness. If you're a medical quack and you hurt someone, there's a law against that.
"But if you're a medical quack and you stand on the street corner preaching that you have an elixir that cures cancer and saves lives, no one throws you in jail."
Holocaust deniers spread conspiracy theories such as that Anne Frank's Diary was a hoax, and that the gas chambers were secretly built after the war.
But whether free speech should include the freedom to say such things has been the subject of furious debate on both sides of the Atlantic. Nine European countries have laws against Holocaust denial - and supporters argue that this is the one issue that crosses the line because it is offensive to both the dead and the survivors.
In the UK, the free speech debate has focused on religious hatred: the government says it will outlaw incitement to hatred of believers. Opponents of the measure, including comic actor Rowan Atkinson, say it's an attack on free speech.
The gas chambers and crematorium at Birkenau, Poland
However, in the case of the Holocaust, Lipstadt says she recognises a case for laws in the lands that formed the heart of the Third Reich.
"Germany and Austria are not so far past the Third Reich. So I can understand that the swastika symbol, Mein Kampf, Holocaust denial, being a neo-Nazi and all the rest have a certain potency there that they would not have in the United States," she says.
"And Austria is a democracy. If the citizens of Austria were against these laws, they could change them. Austria and Germany are different, but I would not support those laws being instituted elsewhere."
Lipstadt says the reason she is generally opposed to outlawing Holocaust denial is not because she fails to recognise how deeply offensive it is but because such laws tend to turn cranks into martyrs.
"I am not interested in debating with Holocaust deniers," she says. "You wouldn't ask a scientist to debate with someone who thinks the Earth is flat. They are not historians, they are liars. Debating them would be nonsensical.
"But we also should not allow them to become martyrs. Nothing is served by having David Irving in a jail cell, except that he has become an international news issue.
"Let him go home and let him continue talking to six people in a basement.
"Let him fade into obscurity where he belongs."