Bradley Smith, director of the Campaign to Decriminalize World War II History and co-founder of CODOH (Committee for Open Debate on the Holocaust), is struck by the absence of gas-chamber evidence in museums devoted to the Holocaust.

"After tens of millions of tax dollars spent at the United States Holocaust Memorial Museum, there is not one exhibit-not one-that demonstrates that one homicidal gas chamber existed anywhere in Europe under German control or occupation," Smith says. The museum, in Washington, D.C., has a casting of a gas chamber door from Maidanek in Poland. (

You don't need an original gas chamber in a museum to prove the Holocaust, says Alex Grobman, co-author of "Denying History: Who Says the Holocaust Never Happened and Why Do They Say it?" (University of California Press, 2000). He visited Auschwitz and other concentration camps with his co-author, Michael Shermer, the editor of "Skeptic Magazine," who is not Jewish .

"The deniers can keep you going," Grobman says. "There's always a next question: 'How do I know this is the one they used?'" Their questions raise another, more fundamental one: "How do you know, or prove anything in history?"

"What if someone says that no physical evidence of slavery exists," Grobman posits. "Do you have to produce the chains and whips and ships in which the slaves came?" He adds, "Holocaust denial is not only a Jewish issue. If you succeed in destroying one group's history, you can do it with anyone's."

"The deniers are the only ones questioning the existence of gas chambers. The German and Polish governments aren't questioning it." What's needed to confirm historical events is "a confluence of information" supplied by a series of "building blocks," Grobman says. There is more than enough evidence: orders for Zyklon-B gas, blueprints and building materials, confessions of camp guards and commandants, diaries by sonderkommandos (whose job it was to remove the dead bodies from the gas chambers), and photographs. (

But Smith, who is 74, puts little faith in eyewitness accounts, such as the more than 50,000 taped by Spielberg's Shoah Foundation project. "I'm burned out on `testimonies' by Jewish survivors," he says, referring to the writings and oral testimony of Elie Wiesel, Simon Wiesenthal, and Abraham Bomba (the "Barber of Treblinka" in "Shoah"), which he calls "lies."

"Survivor testimonies are the weakest link in all the Holocaust literature. Even today the Internet is flooded with old survivors going around to schoolchildren, talking about the unique monstrosity of the Germans. Some of their stories are so goofy that it's like reading a Woody Allen script-one that he decided not to use," says Smith, who launched a revisionist outreach campaign on college campuses in the early '90's by placing a series of ads directing students to his Web site in more than 50 student newspapers.

Weber, who spoke to a number of survivors at the 1983 American Gathering of Jewish Holocaust Survivors in Washington, D.C., is somewhat less dismissive. "I think survivors tell the truth when they describe their own experiences. It's when they talk about events of which they have no personal experience or knowledge, that their testimony is more suspect."

"We try to appeal to the facts, to rational explanations, not to the emotions," he says, pointing out with evident satisfaction that many early assertions about Nazi atrocities have been "quietly dropped" or emended over time. For example, he says, no one now believes the once-authoritative evidence for gas-chamber killings at Dachau and Buchenwald reported at the Nuremberg Trials. "Even Simon Wiesenthal admitted there were no extermination camps on German soil," Weber says.

Concentration camps on German soil may not have been used as extermination centers, says Grobman, a former director of the Simon Wiesenthal Center in Los Angeles. But Germany was the site of gassing installations in which the Nazis used carbon monoxide to "euthanize" mentally ill and disabled Germans, and these killing centers were precursors of the gas chambers. Because Germans objected to such distasteful activities in their own backyard, the Nazis set up Auschwitz and the other death camps in Poland, Grobman says.

Weber argues that there has been a "general reduction in the overall death toll" of Jews at the hands of the Nazis. "There is no prominent historian of the subject who will support the six million figure, but average educated Americans automatically repeat it." And the original figure of four million dead at Auschwitz presented at the Nuremberg Trials has been "downsized" to a little over a million.

According to the U. S. Holocaust Memorial Museum, the estimated number of Jewish fatalities during the Holocaust is usually given as between 5.1 and 6 million victims.

The most recent authoritative figures come from Wolfgang Benz, a German historian and expert on anti-Semitism, Grobman says. Using the same criteria as his predecessors, such as population demographics before and after the war, numbers reported transferred to camps, numbers estimated or reported killed, including in special actions by Einsatzgruppen, and numbers liberated from the camps, Benz arrived at a higher number: 6,269,097. Raul Hilberg has put the figure at 5,109,822. For Auschwitz, the figure is probably between 1.2 and 1.5 million.

On the subject of evidence, Smith draws a parallel with the war in Iraq. "After 60-odd years it is time to admit publicly that there were no German WMD's [gas chambers]," he says. "Just as the Iraqi WMD fraud morally justified the American invasion of Iraq, the United Nations used the German WMD fraud to justify the creation of a Jewish state on land occupied by Arabs."

"The Shoah [the Hebrew word for "holocaust"] is frequently exploited in America and Israel to deflect any criticism of Israel," and "allows Israel to trump other nations' sufferings," Weber quotes from an article by historian Tony Judt in a January 2005 issue of "The Nation." (Judt is Jewish, Weber is quick to point out.)

It may be tempting to dismiss Holocaust deniers as members of a "lunatic fringe," but they have a "profound impact on the collective mindset in the Middle East," says Rabbi Abraham Cooper, associate dean of the Los Angeles-based Simon Wiesenthal Center. "They're heroes among the Muslim and Arab elites."

Abraham H. Foxman, national director of the Anti-Defamation League, a Jewish anti-discrimination organization, says "At first we wouldn't `answer' the revisionists," explaining that there have been three types over the years: old Nazis trying to whitewash Germany's image, Neo-Nazis, and, finally, "classic anti-Semites."

But revisionist David Irving's 2000 libel suit in London against Deborah Lipstadt, an Emory University Holocaust studies professor, and her publisher, Viking Books, "forced the issue," Foxman says. "We had to support the defense."

Irving lost the case, in which he sued Lipstadt for calling him a "Holocaust denier" in her 1993 book "Denying the Holocaust: The Growing Assault on Truth and Memory."In the future, there is bound to be more to defend. "In the old days, a student who was assigned to write a paper on the Holocaust would go the library and find a hundred books, maybe two of them denying it," Foxman says. "Now there are a whole slew of denial sites on the Internet. It's difficult to differentiate between what is legitimate and what isn't."

"There are still people who can stand up and bear witness," Foxman continues. "Twenty years from now, there will be more books, more Web sites, more films-maybe even an anti-`Schindler's List'," he speculates. But there won't be more survivors.