A place of green mountains and clear streams, the Swat valley was once known as the Switzerland of Pakistan. But last week, the Taliban seized control of the region's main town, Mingora, putting it at the center of a crisis that threatens the stability of the West's main ally in the world's most fractious region.

Up to half a million refugees are fleeing the area as the military launches an offensive to oust the militants —- a battle that Prime Minister Yousuf Raza Gilani on Saturday called "a war of the country's survival."

The future of Pakistan, the war in neighboring Afghanistan and the security of the only nuclear arsenal controlled by an Islamic nation could hang in the balance.

Pakistan, Afghanistan

S. Rashid Naim, a senior political science lecturer at Georgia State University, explained what's at stake as Islamic radicals contend for control of Pakistan with the religiously moderate governing class:

"In the worst-case scenario, Pakistan could descend into a full-scale scale civil war. Such a development would be a catastrophe not only for the people of Pakistan but also for U.S. goals in the region. The war in Afghanistan would, in effect, have spread to Pakistan and it would draw the U.S. and its allies into a wider conflict with unpredictable consequences. ... More U.S. troops and treasure would have to be expended in a long drawn-out conflict which might go on for decades. Our experience in Iraq at the height of the civil conflict there would be a tea party compared to what would await us if we got involved in a Pakistani civil war."

Nuclear arsenal

As Kamran Bokhari of the global intelligence firm Stratfor told the Toronto Star last week, "Pakistan is the only country that has both nukes and jihad."

Its weapons are the product of another conflict: a long-standing dispute with India. Created as an Islamic majority state when mostly Hindu India gained independence in 1947, Pakistan has repeatedly engaged in armed clashes with its neighbor over territorial disputes. By 1998, both had developed and tested nuclear weapons.

Specifics of Pakistan's nukes are secret, but it's estimated there are upward of 100. Pakistan says it stores the weapons disassembled in secure sites around the country, and separate from the missiles needed to deliver them. But presumably, to be an effective deterrent, they can be quickly assembled and ready for launch.

The Pakistani government and President Barack Obama say concern over the security of the nuclear weapons is overblown, and the country's still-powerful army gives top priority to guarding them.

"I'm confident that we can make sure that (they are) secure," Obama told reporters last week, adding the army "recognizes the hazards of those weapons falling into the wrong hands."

Reason to worry

Former U.S. Sen. Sam Nunn, a Georgia Democrat who chaired the powerful Armed Services Committee, has devoted himself since leaving office to leading the Nuclear Threat Initiative, a group that seeks to decrease the threats posed by nuclear, biological and chemical weapons. Though he was an informal adviser to Obama during the presidential campaign, he doesn't share the president's sense of assurance about the security of Pakistan's nuclear weapons.

"I wish that I had the confidence that we really know," he said in an interview. "And I'm glad that some of our top officials believe that the Pakistan military is dedicated to protecting those weapons. And I have no doubt that the top levels of the Pakistan military are."

But, he said, "We're not doing our own on-the-ground assessment. We don't have access. So what you're hearing in the statements of confidence is that top U.S. officials are confident that top Pakistani officials fully intend to protect their nuclear weapons. The real question is, the generals aren't guarding those weapons. The privates are —- the young people are. And Pakistan has become more radicalized. Weapons security depends on personnel security. And that's one that's a big question mark, as the country becomes more subject to revolutionary-type zealots."

Nunn said he is worried that, even if the weapons are secure, the material used to make them —- highly enriched uranium —- is not.

What to do

Nunn said he assumes Pakistan has no intention of giving up its nuclear weapons, so he believes the top priority should be to persuade the Pakistanis to cooperate in "blending down" their supply of bomb-making materials so that it is no longer weapons-grade.

"Highly enriched uranium is what terrorists would make a weapon out of, and it's the easiest material to work with," he said.

For Naim, the focus is on getting Pakistan's government to take measures to save itself by restoring its credibility with its people. Most immediately important, he says, are eliminating endemic government corruption and restoring the country's independent judiciary —- crippled under past President Pervez Musharraf, whose removal of the Supreme Court's chief jurist was only recently reversed by current President Asif Ali Zardari.

"The two main assets that the Taliban have in their campaign against the Pakistani government is the perception that they are committed to the rule of law, their excesses aside, and that they are not corrupt," Naim said.

The Pakistani people, he said, "understand that a civil war is a no-win situation for all sides. A combination of statesmanship from their leaders and support from their friends around the world will allow the situation to be dealt with and an international catastrophe with unpredictable outcomes avoided."

Compiled by Sunday A-section Editor Bill Steiden, External Content Editor Tim Ellerbee and staff writer Jim Galloway. The AP contributed to this article.

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