Ernst Zundel was framing a painting at his retirement home, high in the Smokey Mountains of Tennessee, when a van pulled into his driveway followed by three police cars. "It was a whole armada," he recalls. "I knew what was coming next."

The van was from the U.S. Immigration and Naturalization Service. "They put me up against my pickup truck, spread-eagled me, and said I was being arrested and deported. Within five minutes, I was gone."

That was Feb. 17, 2003. Since then, he has not seen his wife or his home. In fact, he has yet to get out of solitary confinement.

Mr. Zundel was whisked back to Canada, the country he had abandoned to escape the 20-year series of prosecutions that had made him its most recognized extreme right-winger. Canada, in turn, wants to whisk him back to Germany, where he faces at least five years in prison.

Ironically, the battle he is waging against that deportation could make the famed purveyor of Holocaust-denying, neo-Nazi material a champion of civil liberties.

Mr. Zundel is confined to a Toronto detention centre because the government is holding him on a national security certificate -- the controversial and Draconian procedure usually reserved for terrorist suspects.

Now, just as he once compelled Canada's courts to grant him freedom to express his views, he could again break constitutional ground. This spring, the Ontario Court of Appeal is to hear his bid under the Charter of Rights and Freedoms to quash the certificate. Win or lose, its ruling will probably land in the Supreme Court of Canada, which could declare the certificate unconstitutional.

If that happens, he will be a mixed blessing to rights advocates. He is now 64 and into his second year in jail, but Mr. Zundel seems every bit as unrepentant and provocative as when he first captured public attention in the early 1980s.

"The Jewish community wants me on my knees," he says in an exclusive interview. "I am the last man standing who has not apologized. It would be the height of indignity for me to do that."

A security certificate is signed by two federal cabinet ministers who, based on secret intelligence, decide that an immigrant should be deported as a danger to Canadian citizens. Even the alleged spies and terrorists normally targeted this way are not permitted access to the precise allegations against them.

Of the 27 security certificates issued since 1991 -- just five since the 9/11 attack -- virtually all have involved suspected terrorists from such countries as Iran, Lebanon and Algeria. Why, then, use such an extreme measure against a Holocaust-denier?

"It is tragic that the whole Western world has deteriorated," Mr. Zundel says. "We are going to be living in Stalinist-time dictatorships."

His lawyer, Peter Lindsay, maintains that the case goes straight to the heart of Canada's response to terrorism. "Mr. Zundel lived here from 1958 to 2000 in a very public way. In all that time, he hasn't committed a single crime. He has been charged a number of times unsuccessfully for things he has said or pamphlets he has distributed, but never for an act of violence. He is not some sleeper agent skulking around in the shadows."

Slapping his client with a security certificate, Mr. Lindsay argues, is just the sort of abuse civil libertarians warned of after 9/11. "The problem is that this law doesn't just get applied to Ernst Zundel. It gets applied to other people out on the fringes of our society. There is an old expression that hard cases make bad law. Well, there is no harder case than Ernst Zundel."

Although the government case relies heavily on accusations revealed only in secret to a judge, an unclassified "summary" compiled by the Canadian Security Intelligence Service accuses Mr. Zundel of being a dangerous preacher of anti-Semitic, white-supremacist hatred. Even if he doesn't advocate violence, it reads, he is dangerous because he's seen as a guru by extremists who do embrace violence.

CSIC describes the white-supremacist movement as a network of groups with a common racist ideology. "Many followers are attracted by Zundel's messaging, his dedication to the cause and his personal charisma," according to the summary. "By his comportment as a leader and ideologue, the service believes Zundel intends serious violence to be a consequence of his influence."

To Mr. Zundel, this is guilt by association. How others interpret and apply his writing is not his business, he says: "I am not the policeman for the right." He admits to speaking at meetings attended by "headline-seekers," but he insists that he resents how their crude tactics marginalize his views.

"The one hallmark that has always earned me the title of being a coward in our circles is that I disdained the use of violence," he says. "I never joined any of these right-wing groups because they were politically impotent."

The inordinate secrecy of the security certificate procedure has left Mr. Lindsay ill-equipped to attack the CSIS allegations. He says he can only guess what facts, hearsay or falsehoods may pepper the classified government documents.

"There could be someone lying through their teeth in evidence that could be attacked and ripped to pieces. I believe in an adversarial system, where both sides can challenge the other side's evidence in an open forum. I don't care whether it is Ernst Zundel or anyone else; there should be one system of justice that works for everybody, including the marginalized and those no one else cares about."

Of course, the government isn't alone in considering the man a threat. "Ernst Zundel epitomizes and sanctions the worst form of Holocaust denial," contends Bernie Farber, a spokesman for the Canadian Jewish Congress.

"Once he had renounced his Canadian citizenship, which is how we see it, there was no need for us to welcome him back. We should not welcome a person whose life ambition it was to foment hatred."

Security certificates ought to be used sparingly, Mr. Farber concedes, but Mr. Zundel's status with violent neo-Nazis makes him a genuine security risk. "He provides the kind of support, succour and oxygen to those who do commit violent acts. Ernst Zundel is not a clown. He is a serious player in the neo-Nazi scene worldwide."

Mr. Zundel came to Canada in 1958 at the age of 19, but was never granted full citizenship. Soon after arriving, he fell under the influence of Adrian Arcand, the famed ultra-rightist in Quebec, and grew obsessed with his belief that Germans had been defamed by "propaganda" stories about their unspeakably brutal treatment of Jews.

"I realized I was a brainwashed young German," he testified last month before Mr. Justice Pierre Blais of the Federal Court of Canada. "It really troubled me and shook me up. . . . I was championing a lost cause. I did it for ethical reasons and for my father's generation, who could not defend themselves."

In 1968, he ran for the leadership of the federal Liberals, infuriating the party establishment. He finished far behind Pierre Trudeau, but nonetheless gained a valuable podium from which to espouse his views. He then moved to Toronto and almost died of cancer, but recovered to throw himself into his graphic-art business, attracting clients ranging from large corporations to Maclean's magazine. He also wrote, under a pseudonym, several books about unidentified flying objects to support publishing pro-Nazi, Holocaust-denial material to send around the world.

By the late 1980s, Mr. Zundel was attracting demonstrations of up to 3,000 anti-racists outside his home in downtown Toronto, receiving hate calls by the score and bombs in the mail. Over the years, he turned his home into a fortress with elaborate security devices, lighting and 24-hour camera surveillance. Even so, in 1995, an arsonist struck, causing $500,000 in damage to his home and that of a neighbour. Finally, in 2000, he ended his stay in Canada, heading south to join his wife in Tennessee.

Now, lodged in an isolation cell at the Metro West Detention Centre, he rarely sees anyone. He takes medication for a heart condition, bad circulation and serious dental problems, and is allowed just 10 minutes of exercise a day. His tiny cell has a cot, toilet and sink, but no toothbrush or towels. If he wants to write, he must perch on a stack of transcripts and use his sink as a desk.

"I do not speak for weeks sometimes," he says. "This is why my voice tends to give way in the courtroom. I'm not bitching, but this is Canada -- it's not Turkistan. I do think somebody is inflicting pain on me."

Mr. Zundel contends that he was turfed out of the United States because of a clandestine request from Canadian authorities, and that U.S. immigration authorities used as a their pretext a minor omission he had made in his paperwork, something that rarely cause a newcomer such grief.

Even so, the odds that he will stay in Canada are heavily stacked against him. His deportation will be carried out if Judge Blais finds that CSIS and the Solicitor-General acted "reasonably" when they issued the certificate. It is an extremely low legal threshold, and no appeal is possible.

Mr. Zundel says his great fear is that the secret evidence against him has been concocted. As a graphic artist, he says he knows just how easy it is to doctor a document or a photograph. "With redigitalization and retouching, anything can be created. They could have me making love to Golda Meir."

Even so, he insists that that he would rather spend his old age in a German prison cell than agree to cease his Holocaust-denying activities.

"For a lifetime, I have fought for equality for Germans to tell their side," he says. "I would be like an intellectual eunuch. People have directed hundreds of thousands of dollars -- millions, actually -- to my legal struggle. I owe these people a fierce fight."

Bench strength

The secret case against Ernst Zundel was compiled by the Canadian Security Intelligence Service.

In a coincidence guaranteed to stoke a thousand conspiracy theories, the man passing judgment on that case used to be in charge of CSIS.

Before being appointed a judge of the Federal Court of Canada in 1998, Pierre Blais was an MP and cabinet minister in the Brian Mulroney government whose portfolios included a stint in 1989 as solicitor-general -- and thus, the minister responsible for the security service.

Because of this connection, Mr. Zundel's lawyer, Peter Lindsay, asked Judge Blais to withdraw from the case. The judge flatly refused.

So, there was a certain irony apparent one day in February when Mr. Zundel, a man with no criminal record who is rated a serious national security risk, testified at length about a litany of threats and acts of violence that have been directed toward him.

As Mr. Zundel was describing how the authorities had failed to notify him when charges were dropped against two Vancouver men accused of sending a bomb to his home, the former solicitor-general exploded.

"This is a very serious matter," Judge Blais boomed, slamming a law book on his desk.

"We are talking about an attempt to murder Ernst Zundel by manufacturing and mailing an explosive device. But he was never told about what happened, and we don't know if these people are still walking the streets or what happened.

"I can't believe this. If there are valid reasons, I want them reported to me."

Kirk Makin is The Globe and Mail's justice reporter.