WOULD YOU CARE," said my Iraqi friend, "to pass an afternoon with Abu Nidal?" I arranged my features into a pose of diffidence. This was March, 1976 in Baghdad, and I had been in town long enough to recognize that sudden displays of any sort of emotion were unwelcome.

But, encouraged by the offhand tone of the invitation, I replied that I had nothing better to do after lunch than meet with one of the world's least wanted men -- a decade ago, Abu Nidal had not begun to achieve the notoriety that he now enjoys since his men fired at random into crowds at the Rome and Vienna airports two days after Christmas.

We drove in an oil-boom limo to the humdrum neighborhood that Abu Nidal lived and worked in as no more than a footnote in the taxonomy of Palestinian nationalism, a shadow thrown on the Middle East by the Iraqi Ba'ath party and its intelligence services.

Expelled from the mainstream Palestinian movement Al Fatah, he had pronounced a sentence of death on its leader Yasser Arafat. This had been warmly reciprocated by the Palestine Liberation Organization chieftains.

Avisit to his obscure and -- I imagined -- carefully guarded office seemed more like the acquisition of a collectors' item for the foreign correspondent. And as it happened, I really did have nothing better to do that afternoon.

In fact, no Kalashnikov-bearing henchman waited in the door of his bungalow. Was this the right house? I walked in.

Abu Nidal rose from behind his desk in a rather discourteous manner. "No doubt," he said, "you have come to enlist in our revolution. Our camp is not far from here."

He was lean and beaky and intense (the Israeli intelligence picture of him, circulated after each new atrocity, seems too blurred for serious identification and has more than once struck me as being of the wrong man). I tried to suppress my boyhood memories of John Buchan characters who hooded their revealing eyes like hawks.

I found it both easy and difficult to decline his invitation to go to the camp. I remember wishing that he had made it at the end of the interview rather than at the beginning. It is easier, after all, to deal with the suggestions of an obvious monomaniac after you have had the conversation that you came for. I decided to strike the pose of a listener, which was just as well since it is not Nidal's preferred mode.

In the next hour or so I was instructed in various matters. The treachery of Arafat and the erosion of his link to the masses was the most often repeated theme.

"The Syrians," said Nidal, "are Arafat's masters." Anwar Sadat, I was told, was "more dangerous to the Palestinians than King Hussein." Only the Iraqi Ba'ath party and, to a lesser extent, the People's Republic of China, had any conception of the struggle.

His next favorite theme was the likelihood -- nay, the certainty -- of physical armed confrontation between Arafat's forces and those of the one true leadership.

Through much of this, I ingested coffee and cigarets and looked at the portrait of George Habash on the wall -- Habash being head of the Popular Front for the Liberation of Palestine and the man who, during the Black September massacres of Palestinians by Jordanians in 1970, had originated the tactic of hijacking as a Palestinian weapon. I made a note of the telephone number (Wasfi 91528) in case it ever came in handy. But Abu Nidal was beginning to sound like every other bore I had ever met in the bars of Beirut -- a fantasy merchant with a phantom army and a grandiose name for it.

Perhaps sensing my lack of response, Nidal cut the rhetoric and leaned forward. "You are from Britain?" he said.

I said, yes, absolutely.

"So why do you think your police must now carry guns? Soon,they will need cannons to defend London from our revolution."

Again, I must have looked insufficiently impressed with this bravado. Europe seemed to be in no danger from this embittered bigmouth.

So he upped the ante and decided to impress me by threatening a friend of mine.

"Do you know Said Hammami?" said Abu Nidal excitedly. I replied that I did. As the head of the PLO office in London, this urbane and gentle fellow had impressed even his sworn political opponents. He had won points, in particular, for a rather courageous series of articles in the London Times, setting out the concessions that the PLO would make in return for a promise of an end to the occupation of the West Bank. Though signed by him, these pieces by Said had been understood as "feelers" for what became the European initiative on the region.

"You may tell Hammami," said my host coldly, "that he is a traitor and that he should beware."

At once, our whole conversation lost its comic-opera quality and became distinctly sinister. It was one thing for Nidal to denounce the Syrians -- everyone knew he was working for the Iraqis. It was one thing for him to praise the Chinese -- never a potent force in the region but still a convenient icon for the ultra-revolutionaries. Predictions of factional violence in the Lebanon, too, seemed pathetically easy to make. But here was a threat being made to someone whom I knew personally.

I don't say that a chill came over me, but I do remember that a slightly unusual interview, an anodyne for a tedious afternoon, had become a thoroughly nasty experience.

We took a stiff farewell of one another I passed out into the heat of the Baghdad afternoon. I had to consider whether what I had just heard was a bluff or not. Abu Nidal was not then to be taken seriously as a political figure, but it was difficult to forget his parting injunction to me: a reminder that I was to warn Said Hammami of the approach of his own death.

Back in London, which still had very few armed policemen, I told Hammami of what had passed in Baghdad and fought down the impulse to change my address. Said gave a sigh, and said that he had heard rumors of all this before.

"My door is always open," he said. "Shall I tell people not to come in?"

I don't know what he told them, but a few months later someone came through that open door and shot Said Hammami dead.

I have felt awful ever since; not every day but often. Did I convey the message with enough urgency? Was I sufficiently serious? How is one supposed to deliver a death threat, by proxy from a crazy enemy, to a valued friend?

Since then, I have followed Abu Nidal with a real interest. I watched his "people" create chaos and mayhem by slaying Yusuf Sebai, a prominent Egyptian journalist, at a conference in Cyprus. I saw how one of his bullets -- fired into the skull of Israeli ambassador Shlomo Argov in London -- precipitated General Sharon's invasion of Lebanon (and added to the danger of London's streets.) I noticed how Abu Nidal slithered, as a hit-man and mercenary, between Baghdad, Damascus and Tripoli. I have sifted the charges and counter-charges -- the PLO saying that he works for the Israeli extremists and the Israelis saying that he provides the cover to make out Arafat as a moderate.

The worst of it is that, having started out as a mere hired gun for various unscrupulous regimes, Abu Nidal may at last be acquiring a real constituency. The 1982 war -- which destroyed their infrastructure in Lebanon -- sent thousands of young Palestinians spinning across the Mediterranean basin, with nothing to lose and nowhere to live and with the disorders that often accompany prolonged exposure to violence and bombardment.

I noticed that a Palestinian recently sentenced to life imprisonment in Cyprus (after the raid on the Israeli boat which led to the Israeli raid on Tunis which led to the Achille Lauro hijacking which led to . . . ) was named Elias Yahya Nasif, and had lost both parents, three brothers and a sister during Israeli raids on Lebanon.

In 1976, the PLO might have been able to discipline him. But not today. Nidal's trumpeting about "peace" as "treason" will not sound implausible to people like that.

Perhaps I shall be accused of credulity and gullibility by those who think that the distinction between "moderate" and "extremist" Palestinians is propaganda; a distinction without a difference. But those who doubt that there are sincere Palestinian negotiators did not know Said Hammami. And those who think that all Palestinians are the same never met Abu Nidal.

Christopher Hitchens, Washington columnist for The Nation and the London Spectator, is the author of "Cyprus."