The most urgent foreign issue on President Obama's plate is "Afpak."

You will be hearing a lot about Afpak — shorthand for Afghan-istan/Pakistan, two neighboring countries whose problems with radical Islamic militants are intertwined. But Pakistan contains the bigger and far scarier danger: al-Qaeda and a network of Taliban militants are based in Pakistan's tribal areas, from which they threaten the stability of the nuclear-armed country.

That's why you should pay close attention to what happened this week in the Pakistani valley of Swat.

Swat was once known as the "Switzerland of Pakistan," a Shangri-La that drew tourists to its high mountains, fruit orchards, and clear lakes. But the valley, set in Pakistan's Northwest Frontier Province, not far from the wild tribal areas along the Afghan border, fell under vicious Taliban control over the past year.

Girls' schools were shut, singing and dancing were banned, and most of the educated inhabitants fled. Any dissenter risks having his head chopped off and propped on his corpse in the middle of the road.

Twelve thousand Pakistani troops have been unable to defeat 3,000 militants in six months of fighting. So here's the big news: The Pakistani government has virtually conceded the area to the militants, saying it will accept a system of Islamic law in Swat and beyond.

The government is supposedly testing the "good Taliban, bad Taliban" thesis also being considered in Afghanistan. The theory is that reconcilable tribal leaders can be peeled off from unreconcilables. Perhaps, but there's scant sign this can work in Swat.

The deal was cut with an older insurgent leader, Sufi Mohammed. Supposedly, he will persuade tougher Taliban, such as his estranged son-in-law Maulana Fazlullah, to lay down arms. Pakistani defense analyst Ikram Sehgal told me by phone from Karachi, "They are trying to isolate the hard-core terrorists from the moderate militants. I think it is a time of trial, to see if this works."

Critics say the deal is a desperation move, made by a weak civilian government and an army that doesn't know how to fight the insurgents. "The Pakistani army has been remarkably ineffective," said Dan Markey, a South Asia expert at the Council on Foreign Relations. He said the army, which is trained to fight land wars against India, lacks the counterinsurgency skills to "hit bad guys and not good guys."

As a result, many innocent civilians are killed, leading locals to accept the Taliban as the lesser of two evils. (That may account for the warm welcome Sufi Mohammed received in Swat after the deal; poor people are desperate for the violence to stop, whatever it takes.)

The army has an additional problem, Markey said. Although civilian and military leaders now recognize that the militants threaten the state, the army is uncomfortable about killing Pakistanis. "So when someone offers them a clever way out, they are inclined to look at it," Markey said.

However, militants have failed to honor past government deals. And, as Markey noted, there's no indication that Sufi Mohammed has any control over hard-core Taliban.

Top Pakistani experts on Islamic militants, such as author and journalist Ahmed Rashid, are horrified by the deal. "It's a surrender," Rashid said emotionally. "It is a major psychological victory for the extremists, and a major concession by the state to extremism. ... How could they let the Taliban take over one of the most strategic valleys in Pakistan, only 100 kilometers (60 miles) from the capital, Islamabad?"

That question remains unanswered. Will the Swat militants permit girls' schools to reopen, civil servants to return to their jobs, and secular residents to return home safely? We'll soon see.

When asked about Swat at a small meeting with journalists at the World Economic Forum in Davos last month, Pakistani Prime Minister Yousuf Raza Gilani said diffidently, "Swat is not so big that we should be concerned." He added, "All of its areas are all right except for (the capital) Mingora, which will take a few more days and it will be all right."

I would have felt better if Gilani had asked for more U.S. counterinsurgency training to help his military defeat the hard-core militants. Hopefully, Pakistani army chief Ashfaq Parvez Kayani will discuss this seriously with U.S. officials when he visits Washington next week.

Reach Trudy Rubin at (Unknown address).

Trudy Rubin is a columnist and editorial board member for the Philadelphia Inquirer. Reach her at trubin@phillynews.com.