JUDY WOODRUFF: Next: a new urgency to resolve escalating tensions between the U.S. and Pakistan.
Margaret Warner has our report.
HILLARY RODHAM CLINTON, U.S. Secretary of State: It is no secret that our relationship of late has not been an easy one.
MARGARET WARNER: Diplomatic understatement from America's top diplomat, Friday in Islamabad.
The secretary of state was in Pakistan's capital to press one of America's most vital and mercurial allies in the fight against militants who are still wreaking havoc in Afghanistan, as the U.S. begins drawing down its forces there.
Washington is fuming over Pakistan providing safe haven and otherwise aiding extremists, like the Haqqani militant network and the Afghan Taliban.
On her way, Mrs. Clinton stopped Thursday in Kabul and with Afghan President Hamid Karzai by her side warned that Pakistan could not let the current situation continue without paying a price.
HILLARY RODHAM CLINTON: The terrorists operating outside of Pakistan pose a threat to the Pakistanis, as well as to Afghans and others. And we will have ideas to share with the Pakistanis. And they can either be helping or hindering.
MARGARET WARNER: She brought a high-powered delegation to Islamabad to reinforce her message: the new director of the CIA, David Petraeus, and the new Joint Chiefs chairman, General Martin Dempsey. She conceded relations had hit a dangerous low point.
HILLARY RODHAM CLINTON: We have seen distrust harden into resentment and public recrimination. We have seen common interest give way to mutual suspicion.
MARGARET WARNER: Despite the tough talk, her trip was designed to stabilize the relationship as well, says former State Department adviser Vali Nasr.
VALI NASR, Former State Department Official: I think the Obama administration understands that the relationship with Pakistan spiraling out of control will jeopardize their ability to leave Afghanistan.
MARGARET WARNER: Several incidents this year have made a hard road even rockier: the January killing of two Pakistani men by a CIA contractor, Raymond Davis; the U.S. mission to find and kill Osama bin Laden in May, undertaken without informing Pakistan; and a spate of bloody attacks on U.S. soldiers, on an international hotel in Kabul, and on the U.S. Embassy and NATO compound there that American officials believe were the work of the Pakistan-backed Haqqani network.
Late last month, the outgoing chairman of the Joint Chiefs, Admiral Mike Mullen, laid out the charge bluntly and publicly.
ADMIRAL MICHAEL MULLEN, Joints Chiefs Chairman: The Haqqani Network for one acts as a veritable arm of Pakistan's internal services intelligence agency.
In choosing to use violent extremism as an instrument of policy, the government of Pakistan and most especially the Pakistani army and ISI, jeopardizes not only the prospect of our strategic partnership, but Pakistan's opportunity to be a respected nation with legitimate regional influence.
MARGARET WARNER: Long preoccupied with its archrival to the east, India, Pakistan has wanted Afghanistan to the west to remain weak and non-threatening and many have viewed Islamic extremists as an instrument to ensure that. The question in Washington: how to divert Pakistan to a different course.
PETER TOMSEN, Former U.S. Envoy to Afghanistan: We have to adopt a tougher line towards Pakistan. We can begin by conditioning the billions and billions of dollars of military and also economic assistance to Pakistan.
MARGARET WARNER: Peter Tomsen, who was U.S. special envoy to Afghanistan 20 years ago, says it's time to face the fact that the U.S. and Pakistan have fundamentally different interests in Afghanistan.
PETER TOMSEN: In a war, you always have an adversary, and we have come to the conclusion that Pakistan is an adversary, both in Afghanistan, but also on global terrorism. We must treat Pakistan as an adversary, and not accept their claims that they're not involved with these terrorist organizations inside Pakistan.
MARGARET WARNER: But Vali Nasr says the U.S. cannot afford to sever ties or cut off the billions in aid to Pakistan right now.
VALI NASR: Every one of our assumptions about our timetable of getting out of Afghanistan, our success on the ground with military operation has been predicated on the kind of at least minimal cooperation we have had with Pakistan over the past two years.
If that cooperation ceases to exist and our relations get any worse than they are currently, it's very difficult to see how the United States can meet its deadlines in order to be able to withdraw from Afghanistan.
MARGARET WARNER: The Afghan war endgame, as the U.S. sees it, is to continue hitting militants on both sides of the border with or without Pakistan's assistance, while trying to draw them to the Afghan peace talks at the same time.
Nasr says the Pakistanis won't cooperate, unless they also have a seat at that bargaining table.
VALI NASR: Also, I think the Pakistanis have used this meeting in Islamabad to push the United States to envision a much more direct role for Pakistan in the peace negotiations. Pakistan so far has been consulted on the peace process and has been pressed to bring the Taliban to the table, but has not a direct role in a negotiation. And this is something that they very much wish to have.
MARGARET WARNER: But Tomsen warns that could be a dangerous course to take.
PETER TOMSEN: Pakistan has interests, strategic interests in Afghanistan, very important interests in Afghanistan, as do all Afghanistan's neighbors. But those interests do not extend to choosing the ruler in Kabul, as they have done in the past.
We shouldn't be doing these exercises of direct involvement in the Afghan political cauldron because nobody understands or really can be successful in that cauldron.
MARGARET WARNER: As if to prove that, even as Secretary Clinton was still in the region, Afghan President Karzai threw a curveball Washington's way in an interview with Pakistan's Geo TV.
HAMID KARZAI, President of Afghanistan: If Pakistan is attacked, Afghanistan will be there with you.
(through translator): If fighting starts between Pakistan and the U.S., we are beside Pakistan.
MARGARET WARNER: Whatever Karzai's motive, it underscored how maddeningly impenetrable the politics of South Asia can be.