It is easy to imagine: a disgruntled employee at a nuclear facility, after years of fudging accounting records, spirits away dozens of kilograms of highly enriched uranium (HEU), selling it to a shadowy and well-financed buyer. The buyer, a terrorist group with al Qa'eda sympathies, fits the illicitly purchased HEU into a crudely fashioned explosive device, the blueprints of which were obtained online. The finished product is a 10-kiloton nuclear bomb capable of levelling Wall Street, large swathes of Mumbai or any densely populated area.
For years experts have grappled with this sort of nightmare scenario, most notably following the Soviet Union's collapse when its expansive nuclear arsenal was left vulnerable. It is difficult to calculate the odds of terrorists obtaining warheads or nuclear materials, or predicting a coup that puts radicals in charge of these weapon. But speculation over where such scenarios could take place is centring on Pakistan.
"Pakistan is the issue today because Pakistan is unstable," said Kenneth Luongo, the president of Partnership for Global Security, a Washington research organisation, and former adviser on non-proliferation policy to the US secretary of energy during the Bill Clinton's presidency. "Russia was the flashpoint 15 years ago because Russia was unstable. Whenever there is an unstable government and nuclear weapons, there is going to be a potential flashpoint."
When Barack Obama assumes the presidency on Jan 20, he faces a situation in Pakistan rife with violence and ideological struggle. According to US and British intelligence, al Qa'eda has regrouped in Pakistan and is planning acts of international terrorism. The country's newly elected civilian leadership is struggling to keep in check the rise of radical religious movements and a new generation of weapons scientists and technicians with uncertain loyalties.
And its military, the ultimate authority over the country's nuclear arsenal, is strained by the fight against Taliban and al Qa'eda militants near its border with Afghanistan while still proving a credible threat to its arch-enemy, India. "Now we're facing a near-war situation in which the army has lost something like 2,000 soldiers fighting fanatics in places like Waziristan," said Pervez Hoodboy, an active political commentator and chairman of the department of physics at Quaid-e-Azam University in Islamabad.
"The problem now is one in which a part of the army is colluding with the Taliban, which is one of the reasons that makes this situation so murky. If the army stays together, then the status quo remains. If it starts disintegrating under further attacks by the Taliban or war with India, then we could face a darker scenario." Amid the fray, the country is managing an estimated 60 nuclear weapons, an array of declared and undeclared nuclear reactors and weapons facilities and thousands of personnel with sensitive knowledge. Guarding this sprawling infrastructure can be expensive and laborious, requiring a labyrinth of security networks and monitors to keep an eye on those with access to weapons and information.
What Pakistan has done to secure its nuclear programme is essentially unknown, said Charles Ferguson, a nuclear security expert at the Council on Foreign Relations, a security research organisation based in New York. "We're getting some information, but the question is, how credible is it?" One of the certainties, he said, was that some US policymakers feared Pakistan contained the elements for disaster: large areas of territory controlled by militants, an unstable government and a nuclear programme founded on material that could be manipulated by amateurs into a crude atom bomb.
"So not only do we have al Qa'eda forces and other terrorist elements in the region, not only do we have potentially unstable and radical elements inside the government, but we have a nuclear weapons programme that's mostly based on HEU," Dr Ferguson said. "And HEU is the best material to use in a relatively simple nuclear weapon called a gun-type device." There is no shortage of nightmare scenarios that come to mind.
What happens if radical military officers steal a warhead and threaten to use it on India? Are blueprints for making bomb fuel and a warhead being illicitly sold in a repetition of Pakistan's famed nuclear scientist, Abdul Qadeer Khan? Whether these scenarios transpire largely depends on the military, whose loyalties have increasingly come under scrutiny. Recent reports in The Sunday Times and Pakistani media suggest fissures in the army, most recently in the case of a former Pakistani army official who was killed in November after threatening to expose secret agreements between army officers and the Taliban.
After its invasion of Afghanistan in 2001, the United States began fighting militants deep inside Pakistan, launching commando raids from Afghanistan and hellfire missile attacks from unmanned aerial drones. It also appears to be hedging its bets with Pakistan's arsenal, boosting aid aimed at securing its nuclear assets but also preparing for the worst. In 2006, the US government reportedly held war games in which its military intervenes to secure or destroy Pakistan's nuclear weapons in the event of major political instability. One of the scenarios, The Washington Post reported in 2007, involved how the US would contend with a rival faction taking power and wielding nuclear weapons "not necessarily to use them but to wield them as a symbol of authority".
Yet participants in the exercises reportedly concluded there were no "palatable" ways to forcibly secure the weapons. "It's an unbelievably daunting problem," a former Pentagon official, who took part in the war games, was quoted as saying. Since September 11, the United States has also invested about US$100 million (Dh365m) in helping to bolster Islamabad's nuclear security systems, Mr Luongo said. The assistance has dovetailed with other security features introduced by Pakistan after its first nuclear tests in May 1998, including a more formalised command-and-control structure, personnel reliability systems and accounting safeguards.
"It's imperfect, just like everybody else's system is imperfect," he said. "But I don't think you can deny that significant steps have been taken and that they [Pakistani authorities] take the issue seriously." Still, he and other experts say the US can only go so far in pressuring Pakistan to improve security. Pakistan is not party to the Nuclear Non-proliferation Treaty, the international regime governing relations between nuclear weapons and non-nuclear weapons countries. Attempts by the United States and other legal nuclear weapons countries to assist non-signatory nations - the so-called nuclear-armed pariahs: Pakistan, India, Israel - with their weapons programme could violate the agreement.
And, like most other nuclear-armed nations, Pakistani authorities have been reluctant to give outsiders access to their most prized defensive assets, which are seen as the country's main deterrent to India. They allegedly bristled at the idea of allowing US officials, after September 11, to fit on their warheads American-made permissive action links, or PALs, which act as coded locks that are designed to prevent unauthorised individuals from using them.
The Pakistanis apparently "don't want to go there; it's a bridge too far to cross", Dr Ferguson said. "To put on a PAL, you would have to have some level of knowledge of the design of the warhead." And then there is the issue of the government's role during in Dr Khan affair. Dr Khan, a revered Pakistani nuclear scientist, confessed in 2004 to illegally selling nuclear weapons secrets for nearly 15 years to a wide range of countries such as North Korea, Iran and Libya.
His trafficking ring is believed to have been the most extensive in history, possibly attempting to sell such information to radical groups. The New York Times reported this month that a Pakistani nuclear scientist and colleague of Mr Khan held talks about nuclear weapons with Osama bin Laden and his deputy, Ayman al Zawahiri, a month before the September 11 attacks. In an interview in Feb 2004, Dr Khan reportedly told investigators that he conducted his trade with the knowledge of senior Pakistani officials at the time, including the former president, Gen Pervez Musharraf, and Gen Mirza Aslam Beg, a former army chief of staff.
The way for the incoming Obama administration to stem the sway of radical elements in Pakistan is for the United States to stop providing justification for radical Islamist causes, said Narayanabba Janardhan, a UAE-based analyst specialising in Gulf-Asia affairs. That means steering America away from the policies of George W Bush, which have helped more than any other cause to galvanise support for religious parties in the country.
"How did all these religious groups gain more power in Pakistan? They came to power on the basis of 9/11," said Dr Janardhan. "Post-9/11 American policy towards Afghanistan is what made all these religious groups in Pakistan gain more support. "Even with the best of intentions, if America were to go about making hard moves in Afghanistan and Pakistan, there is a real chance that Islamic elements will acquire power much more than they already have."
While Mr Obama has yet to set out his policy for Pakistan, he has made it clear that he sees fighting militants in neighbouring Afghanistan a priority. Underlining that, his vice president, Joe Biden, was in Pakistan this week on a fact-finding mission. email@example.com