America likes nothing better than putting a name and a face to the Islamic terrorist threat. First, there was Osama bin Laden, until he was killed in Pakistan; then Anwar al-Awlaki, internet recruiter to al-Qa'ida's cause, until he was killed by a US drone attack in Yemen last September. There remains Khalid Sheikh Mohammed, the self-proclaimed architect of the 9/11 attacks, currently on trial for his life in a courtroom at Guantanamo Bay. But now there's a new pubic enemy Number One: Ibrahim Hassan al-Asiri, al-Qa'ida's bomb-maker in Yemen.
Yesterday, a grainy photo of Asiri was being shown again and again on US television, as the country pondered the implications of the new plot for a suicide bomber to blow up an airliner over the US, hatched in the Yemen but broken up by the CIA and its foreign intelligence allies a fortnight ago. This time, apparently, the public was never at risk. No date or flight had been selected for the operation, while the alleged would-be bomber, whose identity has not been disclosed, is either in custody or dead.
But the affair has glaring similarities with an attack that almost did succeed, the "underwear bombing" attempted on Christmas Day 2009 by Umar Farouk Abdulmutallab. He was a Nigerian student recruited by Awlaki and trained in Yemen for his mission, and was a passenger on Northwest Airlines Flight 253 from Amsterdam as it was making its approach to Detroit with 290 people on board.
Fortunately, the device concealed in Abdulmutallab's underpants failed to explode properly – and it is unclear whether the 80 grams of pentaerythritol tetranitrate or PETN (a relative of nitroglycerine used in Semtex and one of the most powerful explosives known) would have been enough to bring down the plane if it had detonated fully. Beyond doubt, however, the episode was a close run thing. Almost certainly the Saudi-born Asiri was as involved in that plot as he was in the latest one.
He has the track record. Four months before Flight 253, in August 2009, his younger brother, Abdullah, died while trying to assassinate Saudi Arabia's anti-terrorism chief, Mohammed bin Nayef, in a suicide bombing, with a concealed device. That bomb did go off, but Abdullah's body shielded his Saudi target from the worst of the blast. Ibrahim Asiri is also believed to have made the bombs hidden in two packages which were found on separate US-bound cargo planes in Dubai and Britain in October 2010. Those planes too, investigators said, were meant to blow up in mid-air close to American cities.
This latest scheme, according to reports yesterday, was foiled by a tip from a Saudi infiltrator into a terrorist cell. But it underscores how AQAP, as al-Qa'ida's operation in the Arabian Pensinsula is known, is the terrorist group's most active affiliate – and the one that preoccupied Bin Laden, if the correspondence from his lair in Abbottabad, released here last week, is any guide.
The public disclosure of the conspiracy came 24 hours after Fahd al-Quso, a senior figure in AQAP with a $5m (£3.1m) price on his head, was killed by a US drone strike. Indeed, some analysts here believe, the unmasking of the bomb plot and the elimination of al-Quso were part of the same operation. On President Obama's orders, the US has stepped up drone attacks in Yemen as well as in the Afghanistan-Pakistan war zone. In the former, Ibrahim Asiri is now surely top of the CIA's hit list.
Given the evident success of the drones in helping to decimate al-Qa'ida's ranks, not to mention the Yemeni government's stepped-up campaign against al-Qa'ida since the departure of former president Ali Abdullah Saleh in November 2011, Asiri's life expectancy may not be long.
But even his death would not end the threat posed by AQAP. Awlaki may have been "taken out", but that did not stop the organisation from taking advantage of Yemen's protracted political instability to take control of great swathes of the country, which they retain today. And while one bomb plot may have been scotched, there is no guarantee that more bombs and plots do not exist. Asiri for his part has reputedly trained successors in his dark arts.
And these arts are getting even darker. The captured device is now being picked apart at the FBI research centre at Quantico, Virginia, but undoubtedly is more sophisticated than the bomb carried by Abdulmutallab. By all accounts it contains little or no metal, making it harder to detect. Whether it would have been picked up by an X-ray system or the body scanners in place at US airports is a matter of dispute. However, it would not have passed through airport security in the US but in a foreign country, where standards could be laxer. It is possible too that al-Qa'ida is seeking to surgically implant a bomb into a "martyr", that would be even more difficult to detect.
Meanwhile, the foiled bomb attempt is generating political heat in Washington over whether word of it was leaked deliberately. Elections are approaching, and as Mike Rogers, Republican chairman of the House Intelligence Committee, said yesterday: "In a political season, funny things happen."
The story was obtained exclusively by The Associated Press news agency, which delayed publication at the request of the Obama administration. Is it stretching cynicism too far to imagine that an official might have leaked information to burnish an unexpected strength taken by a Democratic President into his campaign – his record on combating terrorism?
But such a ploy would be highly risky. Partisan controversy could create a distraction allowing a bomber to slip through – and nothing would be more damaging to an incumbent seeking a second term than a deadly terrorist attack in America's skies. The last thing this White House wants is to drop its guard. As John Brennan, Mr Obama's counter-terrorism adviser put it yesterday: "You never know what you don't know."