It's such a highly charged term, "evil," and so are its recently revived elaborations "evil ones" and "evildoers"—words that President Bush has applied to Osama bin Laden and al Qaeda. That doesn't mean "evil" is a useless term. It can specify something important, but we should know what it is specifying, because tossing the term around indiscriminately can devalue it, rob it of its very specific gravitas. There is evil and there is evil—the word has hierarchies and degrees—distinctions to be drawn and commonalities to be sought, when making comparisons between Hitler and bin Laden, for instance.

One of the curious, paradoxical things I discovered during the dozen or so years I spent examining the ways in which Adolf Hitler's crimes have been explained by historians, philosophers, and theologians (for a book called Explaining Hitler) was the reluctance of so many experts to apply the word "evil" to Hitler. This was in part a kind of displacement syndrome: it wasn't really Hitler who was responsible for Nazi crimes, but "the forces of history" that he embodied. Blame them. Or it was not Hitler himself so much as the irresistible pressure of a distorted ideology. Blame that. Or, for Freudian "psychohistorians," it was not Hitler, it was his unconscious drives. Blaming Hitler, attributing his crimes to him personally, to his conscious "agency," as it's called by the postmodernists (who don't believe in it), was considered a quaint throwback to a less sophisticated era of analysis. But there was as well an understandable reluctance to use a word—"evil"—that had been robbed of meaning and force by over-application.

I found it useful to look into the philosophical literature on the question of defining evil, where one discovers not a single, all-encompassing evil but hierarchies and degrees that distinguish natural evils ("acts of God," in the theological and insurance-company vocabularies) from man-made evils—flu epidemics from anthrax attacks, for instance. And among man-made evils one finds distinctions between the mindset of the perpetrator who does evil under the illusion that he's doing good and that of the evildoer who knows he's committing a crime. The latter falls into a more rarefied category in the literature: one often called "wickedness," which itself can be divided into "ordinary wickedness," "selfish wickedness," "conscientious wickedness," "heteronomous (just following orders) wickedness," and the highest (or lowest) degree, "malignant wickedness"—doing evil for evil's sake. (Even self-professed Satanists can be exempted from the latter category, because they believe that Lucifer deserves to be God. Satan is the good guy; there's just been a big mistake.)

But the defining moment in the learning process, the moment that crystallized the debate over Hitler's evil for me, came during a conversation with the influential British historian H. R. Trevor-Roper. Eventually I came to disagree with the view he expressed, but it dramatically defined one pole of the ongoing argument.

As I recall, during the latter part of my talk with Trevor-Roper a noisy chess tournament was going on in the common room of London's Oxford-Cambridge Club, and I had to lean forward to make myself heard—Trevor-Roper was nearly eighty back then, in 1994. I remember the details because what he said was so memorable. I had asked him about Hitler's consciousness of his crimes—one of the two crucial variables in defining degrees of evil. The other variable is the scale of the crime: at what point does an order of magnitude in the number of murders—the difference between, say, six million and six thousand, or between six thousand and six—make a difference in the order of magnitude of the evil attributable to the perpetrator? Consider the uneasiness of some over the discrepancy between the universally reported September 11 "6,000" and the newer number, now believed to be closer to 4,000. At what point do numbers matter?

Most people (not all) would agree that a difference in degree between six million and six can be discerned, if not precisely defined. But defining degrees of evil involves calculations of both mindset and magnitude, whereby a lower body count might in some cases represent a greater degree of evil or a higher body count a lesser. Stalin's body count, for instance, is now generally considered greater than Hitler's (depending on who's counting), and yet some postmodern Marxists still argue that there's a qualitative difference between Stalin's murders and Hitler's—that Stalinism was a lesser evil than Hitlerism, because Soviet communism was—originally, they say—motivated by utopian idealism rather than Hitlerian race hatred, and the tens of millions of murders were an unfortunate (but really unrelated) "side effect."

The post-Holocaust debate over the definition of Hitler's evil can be said to have begun in 1947, when Trevor-Roper published what was not just one of the first postwar biographies of Hitler but also one of the first postwar visions of his mind: The Last Days of Hitler. He brought to the subject the shrewd perspective of a historian (whose specialty before the war had been the sixteenth- and seventeenth- century religious wars) and the even shrewder perspective of an experienced MI-6 counterintelligence agent whose wartime task had been to maintain liaison with anti-Hitler plotters in Germany.

A few months after the Nazi surrender Trevor-Roper made his way through the rubble of Berlin to Hitler's bunker, hoping to find clues there to the mind of a mass murderer. His official assignment from MI-6 was to combat the "survival myth," as it would soon be called. One of the first signs of the coming Cold War disinformation struggle was Stalin's decision to spread rumors that Hitler was alive and living under Allied protection in the British zone of Berlin (even though by then Stalin seems to have had Hitler's organs stored in jars in Moscow).

Despite the success of Trevor-Roper's mission—to establish the facts of Hitler's last days in the bunker, of his suicide, and of the disposal of his body—the survival myth lives on in tabloid culture (usually in a South American context), perhaps because it speaks to some not unjustified apprehension in the collective unconscious that even though Hitler is dead, the difficult questions he raised about evil and human nature have not been laid to rest.

Trevor-Roper obtained access to the captured aides and flunkies who had participated in the burning of Hitler's body. He tracked down Hitler's last will and political testament, in which Hitler implicitly accused the German people of failing to make the kind of martyrlike sacrifice for the cause that he would make with his suicide, and in which he called on those left alive to continue his holy war against the "universal poisoners of all nations," the Jews.

Based on this and on his later immersion in the stenographic record of Hitler's wartime dinner-table conversations, (known as the "Table Talk"), Trevor-Roper had developed a strong conviction about the nature of Hitler's mind. It was a conviction I evoked with a question that evening in the Oxford-Cambridge Club: "Did Hitler know he was doing wrong when he was committing his crimes? Did he know his acts were evil?"

"Oh, no," Trevor-Roper told me with great asperity. "Hitler was convinced of his own rectitude." (It was striking to see this formulation echoed by a Muslim in Hamburg who defended the motives of the September 11 suicide bombers: "Those who did this had to be convinced they were right," he told Joseph Lelyveld, of The New York Times.) Hitler, Trevor-Roper maintained, didn't think he was doing wrong; he thought he was doing right, doing good. In his own mind he was an idealist. Hitler frequently compared himself to heroic medical scientists like Pasteur and Koch: the Jews were a "racial bacillus"; he was a germ fighter; extermination was a medical measure to stamp out a plague threatening all that was good. That he was dreadfully wrong in this conviction does not of necessity mean that he was knowingly wrong. This is Hitler as true believer—Hitler as Osama bin Laden.

Indeed, those who take this position come close to portraying Hitler as the genocidal equivalent of a suicide bomber. His apparent decision, in 1944, to withdraw troops and trains from the besieged Eastern front in order to expedite the transport of Jews to the death camps is the act most often cited to support this vision of a self-destructive "idealist" Hitler. This is a Hitler who would choose to lose the war, see the destruction of Germany—in effect, blow himself up and end as a martyr in order to maximize the mass murder of the true enemy, the Jews.

The problems implicit in applying Trevor-Roper's true-believer vision of evildoers to the current crisis are dramatized in a report in the Guardian of October 16, 2001, by Jeanette Winterson (cited in The New Republic's "Idiocy Watch"), who wrote,
My friend Ruth Rendell was in conversation at the Cheltenham Literary Festival ... Someone asked a question about pure evil, citing the terrorist attacks on America ... Rendell replied that we could not categorize such attacks as evil, since they were carried out from the highest motives and in the name of freedom. The audience hated this reply—there was a collective and audible shudder. Yet who reading bin Laden's speeches can doubt it? There is no cynicism in the man.
And not long afterward I came upon these words from Stanley Fish, postmodern prof par excellence: "The moral vision of Hitler is a moral vision," he told Bill O'Reilly on the Fox News Channel in a discussion about Hitler and bin Laden. "We have to distinguish between moralities we approve and moralities we despise." In other words, the true-believer rationale can lead to an indiscriminate relativism.

Such remarks illustrate two kinds of problems, evidentiary and moral, raised by Trevor-Roper's view. Assume for the moment that Hitler and bin Laden were indeed convinced of their own rectitude in committing mass murder. This view is unsatisfying to many, because it suggests a lesser degree of culpability, a lesser degree of evil, than if Hitler and bin Laden had been convinced of their criminality. This is a problem that has vexed philosophers since Socrates first insisted (in the Protagoras) that people do wrong only if they are deluded into thinking they are doing right or if they are rendered incapable, by reason of ignorance or mental defect, of knowing right from wrong (the "moral imbecility" of the psychotic killer).

Assigning different degrees of evil to different quantities and qualities of murder may seem at first to be an angels-on-the-head-of-a-pin matter, but it is something we the people routinely engage in when, as juries, we decide the difference between first- and second-degree murder, between voluntary and involuntary manslaughter, very often according to calculations of mindset. In that light I once, perhaps unfairly, characterized Trevor-Roper's view of a Hitler convinced of his own rectitude as "the Menendez brothers defense of Hitler." The brothers, you'll recall, blew away their parents with shotguns before going on a spree with the inheritance, and then claimed in court that they shouldn't be convicted of first-degree murder, because they were sincerely, if mistakenly, convinced that their parents were planning to kill them. They had acted in self-defense. Analogously, in Trevor-Roper's view, Hitler was sincerely, if mistakenly, convinced that the Jews were out to destroy the master race and thus must be eliminated for the good of humanity. And Osama bin Laden was sincerely, if mistakenly, convinced that he had to murder innocents to defend Islam.

At what point, at what order of magnitude, does the number of dead override the "rectitude" rationale? If one "sincerely, if mistakenly," kills six? Six thousand? Six million? Does a holy crusade justify killing an unlimited number of infidels if one "sincerely" believes that one is carrying out God's will to rescue humanity from evil? Could a single person therefore justify killing everyone else and still be thought to be convinced of his own rectitude if he believed it was for the greater glory of God? Is there an accepted ceiling above which no such justification, however sincere, obtains? Common sense suggests that at some point even the most oblivious mass murderer recognizes that he has crossed a border and gone beyond sincere idealism. But who says common sense rules in such cases?

Even if the "rectitude" view leads to one reductio ad absurdum after another, it may in some ways be attractive because it's a perversely comforting vision. Thinking of Hitler and bin Laden as true believers unaware that they are perpetrating evil does not necessarily excuse their crimes, but it does avoid acknowledging an almost unbearable possibility: that human beings are capable of committing mass murder not with an "idealistic" rationale but for self-advancement or self-aggrandizement.

That is the specter raised by those who oppose Trevor-Roper's view of Hitler's evil. Their view was initially represented by Alan Bullock, an Oxford historian who published Hitler: A Study in Tyranny in 1952, and became Trevor-Roper's great rival as postwar Hitler explainer. I say "initially" because Bullock subsequently altered his view, but his original position, still held by many others, depicted Hitler as a believer in nothing at all. Bullock's Hitler was a cynic, a con artist, a mountebank, who didn't even believe his professed anti-Semitism. Whipping up hatred of the Jews was just an opportunistic way to exploit for his own ambition a defeated nation's hunger for a scapegoat. The influential post-Holocaust theologian Emil Fackenheim told me in 1993 in Jerusalem that he, too, believed that Hitler was "just an actor" posing as an anti-Semite.

Bullock subsequently changed his view to one that incorporates elements of Trevor-Roper's true-believer hypothesis: Hitler was "an actor who believed in the part." In other words, Hitler started out as a cynic and an opportunist, but success made him a true believer in the messianic image he'd created.

But in either view, Bullock and Fackenheim impute more knowingness to Hitler than Trevor-Roper did. Evidence that Hitler was conscious of his criminality includes his recurrent efforts to conceal his authorship of the Final Solution. In effect he was the first Holocaust denier, ostentatiously calling the Holocaust a "rumor" in one of his "Table Talk" conversations. Hitler never publicly praised the death camps to the world the way bin Laden publicly praised the September 11 attacks in a tape meant for broadcast shortly after September 11—the one in which he proclaimed, "God has blessed a group of vanguard Muslims, the forefront of Islam, to destroy America." And now we know from the tape released on December 13 that even if he didn't claim authorship in public (perhaps because of his Taliban hosts at the time), he was not shy about boasting and laughing about it in private. And in that tape—"Osama's Table Talk"—he was even more willing to laugh out loud about mass murder than Hitler and his cronies were in their "Table Talk."

In the sometimes paradoxical-seeming hierarchy of evil that philosophers have adumbrated, such willingness to sanction mass murder openly, as a mission from God, might consign bin Laden to a lesser category of evil than the one to which Hitler's somewhat surreptitious and self-protective approach to mass murder consigns him. Bin Laden has done evil, but Hitler was knowingly wicked. That's true only if one accepts the notion that bin Laden is, like Trevor-Roper's Hitler, "sincere"—a true true believer. From the fragmentary knowledge we have of bin Laden's past it's possible to cobble together an argument suggesting a greater similarity to Bullock's revised version of Hitler: bin Laden as an actor who became convinced by his own act.

From Atlantic Unbound:

Interviews: "Terrorism's CEO" (January 9, 2002)
Osama bin Laden, argues Peter Bergen in Holy War, Inc., used corporate-management techniques to turn al Qaeda into the world's preeminent terrorist organization.