The United States, Pakistan, and their coalition allies have two daunting tasks before them: setting up a high-tech dragnet along 1,500 miles of treacherous mountain passes and smuggling roads that make up the Afghan-Pakistan frontier, and tracking down any member of Al Qaeda - especially Osama bin Laden - who may have already slipped across that border.
Whether Pakistan's 600,000-man Army is equipped and prepared to handle this task has become a key question in America's ongoing war on terrorism. And this leaves President Pervez Musharraf with the challenge of demonstrating that he is making his best effort to track down Afghan and Arab militants on one hand, while not suppressing like-minded Pakistani groups so severely that he sets off a civil war.
Special US envoy to Afghanistan James Dobbins said in Islamabad, Pakistan, yesterday that while the US understood that some Al Qaeda and Taliban fugitives may slip through into Pakistan, he had full confidence they could be found and brought to justice.
"I don't think it's possible to prevent individuals from crossing the border," Ambassador Dobbins told reporters. "I think it's possible to apprehend those individuals over time."
Recent news reports and local Afghans suggest that Mr. bin Laden and much of the Taliban establishment have already crossed into Pakistan and are hiding out in autonomous tribal areas, where they share ethnic ties and an Islamist ideology with the populace.
Many Pakistani experts say that the addition of a few charismatic religious extremists to such an environment could have huge implications for Pakistan, a country just beginning to confront the significant influence of its own powerful - and sometimes violent - fundamentalist minority.
"There are two particular and fairly extensive Islamic fundamentalist groups - Harkat-ul-Mujahideen and Jaish e-Mohammed - that have a fairly large following and are dedicated to gaining power, much like the Taliban," says Stanley Bedlington, a retired CIA counterterrorism expert. "Musharraf has to keep his eyes open, make sure he takes great care in dealing with them."
One way the US can help him do that - especially with US use of Pakistan's airbases, aid, and intelligence services, Mr. Bedlington says - is to make sure that Pakistanis receive tangible rewards for their help, and that it gets into the right peoples' hands. "We've got to do things such as the reduction of Pakistan's external debts, which is something like $38 billion. And we can increase the amount of aid in order to show the Pakistani people that they do get something out of this," Bedlington says. "And this should be monitored closely so that this goes to the people who need it and it doesn't get tucked into the pockets of the most corrupt government known - the Pakistani government."
But in Pakistan, the US must walk a fine line between buttressing the strong ally it has cultivated in General Musharraf, or undermining him.
If the US is really serious about pursuing Taliban and Al Qaeda leaders here, many experts say that will entail putting intense pressure on Pakistan's military-intelligence organization, the ISI, and its deep ties to both Pakistani and Afghan extremist forces. The US might even require the ISI's dismantlement. But such pressure could threaten Musharraf, a scenario the US would want to avoid at all costs.
"At some point, our pressuring of Musharraf is going to lead to other, very possibly undesirable consequences," says Andrew Bacevich, a retired Army colonel who directs the Center for International Relations at Boston University. "The US insisting he shut it [ISI] down could be the step too far."
Public opinion is also a concern. "The government of Gen. Pervez Musharraf took a very unambiguous stand against terrorism in Pakistan," says Sajad Haider, a retired air commodore in the Pakistan Air Force and now a strategic analyst in Islamabad. "Pakistan is a country of 140 million people, and it has 2 million Afghan refugees in its midst. Many of them are belligerent and uncompromising.... The last thing Musharraf wants is for Osama bin Laden to be his nemesis."
Like many Pakistanis, Commodore Haider gives the military government of Musharraf high marks for responding quickly to a difficult task. In the past week, Pakistan has sent thousands of troops, deployed helicopters, and set up 300 additional checkposts along its border, particularly in the 25-mile stretch just south of the mountainous Afghan region of Tora Bora. It is there that Afghan militias have declared victory over the last significant force of Arab and other fighters with bin Laden's Al Qaeda terrorist organization.
But age-old smuggling routes, from donkey paths to gravel roads suitable for trucks, criss-cross the border, with only the most informal checkposts manned by tribal police and militias.
"It's impossible to seal the border," says a retired senior officer in the Pakistan Army with extensive experience in Afghanistan who requested anonymity. "Pakistan would have to raise another 500,000 troops to police the border." He pauses. "It's not a border really. It's like a sieve."
The best Pakistan can do, the officer says, is to prepare for the social and political costs of a fleeing wave of Taliban and Arab fighters."The implication for Pakistan is that if they turned up here, they have ready sanctuaries in the madrassas [religious schools]," the Pakistani officer adds. "No one knows what [Taliban Supreme Leader] Mullah Omar looks like anyway. All he has to do is put a shawl over his head and mingle with the crowd. No one will know who he is."
Officials have already begun to clamp down on the thousands of religious schools in Pakistan, which have provided fresh recruits for a dozen militant groups inside the country. Many of these groups, including Pakistan-based Harkat-ul-Mujahideen and Jaish e-Mohammed, have training camps of their own within Afghanistan.
But how this is done will be key to the future of Pakistan. Ret. Gen. Wesley Clark says, "Of course we'll go after [bin Laden and his associates] in Pakistan. But we may not necessarily use the same techniques. We would probably use Pakistanis first. And we probably have special forces guys right now in there, working with the Pakistanis."
Faye Bowers in Boston and Howard LaFranchi in Washington contributed to this report.