Who specifically authorized the worst terrorist outrage ever perpetrated in Britain? Who conceived it? Who built the bomb? And how is it, amid the new controversy over the release of the only man ever convicted in the blast, that investigators never found answers to these most fundamental of questions, and never charged those responsible?

Libyan Abdel Baset Megrahi, who was found guilty of the 1988 Lockerbie bombing, center, is helped down the airplane steps on his arrival at an airport in Tripoli, Libya.
Photo: AP

The Iran of the early 1990s was considerably more circumspect than it is today about its drive for nuclear weaponry. But it was no less ruthless in the pursuit.

And that is why, on August 14, 1993, a very high level group of Iranians, including two cabinet ministers and two military chiefs, sat down together in the city of Mashad to plot their revenge against president Carlos Menem of Argentina, who had had the temerity to scuttle their plans for a rapid march to nuclear self-sufficiency.

The mercurial Menem had first suspended, then severed, Argentina's hitherto fruitful partnership with the Iranians on all things nuclear, terminating the training of nuclear technicians in his country and the transfer of nuclear technology to theirs. His perfidy, Teheran decreed, would not go unpunished.

Menem's initial suspension of the nuclear partnership at the turn of the 1990s had prompted Iran to commission the 1992 attack on the Israeli Embassy in the Argentinean capital that left 29 people dead. Now the Mashad notables were considering where to strike next, poring over the details of three potential targets supplied by one of their men in Buenos Aires, Mohsen Rabani, who had flown in specially for the consultation.

It is not known to this day what the other two potential targets were, because the first location on the list, the AMIA Jewish community headquarters, was quickly approved. Eleven months later, the carefully planned attack was "successfully" executed: a white Renault Trafic van, driven by Lebanese Hizbullah recruit Ibrahim Berro, rammed into the AMIA building, with horrific consequences. The multi-story building collapsed, 85 people were killed and hundreds more were wounded.

That we know the specific details of the atrocity's planning, all the way up through the Hizbullah and Iranian hierarchies to the very door of then Iranian president Hashemi Rafsanjani, is thanks to insistent, methodical investigation by the man who for the last five years has been responsible for bringing the AMIA perpetrators to justice, Argentinean prosecutor Alberto Nisman.

The AMIA probe initially took all manner of wrong turns. It was almost certainly skewed by Menem himself, who told this reporter days after the blast that he feared for his own life, and was not unreasonably terrified by Teheran's demonstrable viciousness and global reach. It was certainly corrupted by some of Nisman's prosecutorial predecessors, descending for a decade into a farce of bribery and cover-up, and earning condemnation from subsequent Argentinean president Nestor Kirchner as a "national disgrace."

But Nisman, defying Iranian death threats and heroically refocusing the probe, two years ago presented sufficient evidence for Interpol to issue arrest warrants for several members of that 1993 Rafsanjani-run, terror-commissioning committee. And so it was that last week, when President Mahmoud Ahmadinejad named Ahmad Vahidi as Iran's new defense minister, the name rang alarm bells and prompted an outcry in Argentina and beyond. For Vahidi, in the early 1990s, was the head of the Quds Force of the Iranian Revolutionary Guards, notorious for its terrorist operations overseas in conjunction with Hizbullah. Vahidi was among the participants in the Mashad meeting. Vahidi, fingered by Nisman, is wanted by Interpol for his role in orchestrating the AMIA bombing.

Delighting in his notoriety, and deriding what one lawmaker described as "the Zionist regime's ominous stance against him," the Iranian parliament on Thursday overwhelmingly endorsed Vahidi's appointment. "Iran has always protected terrorists, giving them government posts," observed the unflappable Nisman when news first broke of Ahmadinejad's choice. "But I think never one as high as this one."

THE OUTCRY over Vahidi's appointment, indeed the very fact that we know of Vahidi's terrorist activity, underlines the dismal contrast between Argentina's initially flawed and corrupted but ultimately rigorous and unflinching investigation of the AMIA blast and the British-American investigation of the Lockerbie bombing. In short, gutsy Argentina got the job done and did right by the victims of the atrocity it had suffered, and the UK and US, those great, powerful, moralizing democracies, failed.

Britain and America are currently embroiled in all manner of controversy and convulsion over the release late last month of the only man ever jailed for the Lockerbie blast, Libyan intelligence agent Abdel Baset al-Megrahi, freed and returned to Col. Muammar Gaddafi's Libya on compassionate grounds as he fights a losing battle with cancer.

The AMIA bombing remains the worst terror attack ever perpetrated in Argentinean territory. The Lockerbie bombing, which saw the deaths of all 259 passengers and crew, and 11 people on the ground, when Pan Am Flight 103, en route from London to New York, was blown out of the Scottish skies on December 21, 1988, remains the worst terror attack ever perpetrated in British territory, and killed more American civilians than any single act of terror, with the sole exception of the 9/11 attacks.

Argentina, after years of false starts, used insiders' testimonies, followed money trails and employed every other tool at its investigators' disposal to trace the incriminating evidence unwaveringly back to Iran and the specific, top-level individuals who orchestrated the AMIA attack. With the assistance of other nations' investigating authorities, notably Germany's, the British and American authorities probing Lockerbie gave every initial sign of doing the same thing.

They recognized an Iranian motive: to avenge the downing, by the US Navy's guided-missile cruiser USS Vincennes, of an Iran Air Airbus in the Persian Gulf five months before Lockerbie, in which all 290 passengers and crew were killed. The US said it had mistaken the civilian airliner for a fighter jet; Iran said the attack was deliberate and vowed revenge; Ayatollah Khomeini promised the skies would "rain blood."