WASHINGTON » As the Obama administration pours 30,000 additional troops into Afghanistan, it has begun grappling with the next great dilemma of this long war: whether to reconcile with the men who sheltered Osama bin Laden and still have close ties to al-Qaida.

The Afghan president, Hamid Karzai, has said he wants to reach out to the leaders of the Taliban, and administration officials acknowledge privately that they are considering the idea. But they warn that the plan is rife with political risk at home and could jeopardize a widely-backed effort to lure lower-ranking, more amenable Taliban fighters back into Afghan society.

The debate, still in its early stages, could shape the next phase of America's engagement in Afghanistan, officials said, and is every bit as complicated as the decision on whether to commit more soldiers, not least because it rekindles memories of the Sept. 11 terrorist attacks.

On Thursday, donor countries, led by the United States, Britain and Japan, are expected to commit $100 million a year to an Afghan fund for reintegrating the foot soldiers of the Taliban with jobs, cash and other inducements. But the allies are less sanguine about dealing with the Taliban's high command, particularly its leader, Mullah Mohammad Omar, and other “;hard-core”; Taliban elements which, the administration bluntly declared last March, were “;not reconcilable.”;

One question is how likely these people are to be enticed by the inducements, given the gains the Taliban has made. Some U.S. officials suggest the debate is premature, saying the Taliban has to be depleted through drone strikes and ground combat before it would return to the bargaining table.

The pros and cons of dealing with the Taliban will loom large at the conference in London this week, where Karzai is scheduled to present his plan for lower-level reintegration.

While Omar remains off limits for the United States, the administration's openness to reconciling with other Taliban leaders has grown since last year, officials say, because of its recognition that the war is not going to be won purely on the battlefield.

“;Today, people agree that part of the solution for Afghanistan is going to include an accommodation with the Taliban, even above low- and middle-level fighters,”; said an administration official, speaking on the condition of anonymity because he was discussing internal deliberations.

Still, any grand bargain is bound to be messy, he said, with the Taliban most likely to demand government jobs or control of large areas of territory in Afghanistan's south, where it now rules by fear. What the United States would be willing to tolerate has become a hot issue inside the administration.

Already, the Pentagon has expressed skepticism about coming to terms with high-ranking Taliban figures anytime soon.

“;It's our view that until the Taliban leadership sees a change in the momentum and begins to see that they are not going to win, the likelihood of significant reconciliation at senior levels is not terribly great,”; Defense Secretary Robert Gates said last week in India.

At the same time, the senior U.S. commander in Afghanistan, Gen. Stanley McChrystal, said recently he could eventually envision a role for some Taliban officials in Afghanistan's political establishment.

Other senior officials, like Vice President Joe Biden, are said to be more open to reaching out, because they believe it will help shorten the military engagement in Afghanistan.

The special representative for Afghanistan and Pakistan, Richard Holbrooke, is also said by officials to be privately receptive, although he expressed doubts in an interview. “;It's very unclear on which basis you can have reconciliation with the Taliban leadership when they are still allied with al-Qaida and pursue policies that would create permanent instability in Afghanistan and the region,”; Holbrooke said.

Part of the problem is that the process could set off unpredictable forces. Some contend it could split the leadership of the Taliban, swelling the ranks of subordinates who accept the Afghan government's offer to lay down their arms. But skeptics argue that it could embolden the Taliban, by making its leaders think they have the upper hand against the Afghan government.

“;The more there is talk of negotiation, the more the Taliban view it as a sign of weakness,”; said Vanda Felbab-Brown, an expert on Afghanistan at the Brookings Institution. “;How do you make sure the reconciliation process does not embolden the Taliban to go on the march?”;

Reconciliation has a troubled history in Afghanistan. In December 2007, Karzai expelled two Western officials for unauthorized contacts with the Taliban. The United Nations said the talks were with tribal elders, though one of the officials, Michael Semple, an Irishman who worked for the European Union, has written extensively since then about the value of negotiating with the Taliban.

There are also inklings of a new openness on the part of Omar. Last September, he stirred some controversy in the extremist world with a public statement suggesting that he put the goal of retaking power in Afghanistan ahead of the global jihad favored by al-Qaida.

Some analysts saw this as a sign of a rift between the two groups and a hint that Mullah Omar might be open to talks. The Taliban, he said, “;want to play our role in peace and stability of the region.”;

In London, Karzai is expected to provide details about reaching out to lower-level Taliban members. One question is whether he will ask the United Nations to remove Omar's name from a “;blacklist,”; which freezes bank accounts and prohibits travel for those on it.

The blacklist is important because the government cannot negotiate with Taliban members whose names are on it. A U.N. Security Council committee said Tuesday that it had removed five senior Taliban from the list, Reuters reported.

For now, U.S. military officials said, the focus will remain on lower-level street fighters.

The hope is that in the next few months, the 30,000 additional U.S. troops will start to make a dent in the Taliban's offensive. Even then, U.S. officials said, any reconciliation would require the Taliban leaders to renounce violence.

“;That's a pretty high bar for the Taliban leadership to clear,”; said Brian Katulis, of the Center for American Progress, a liberal advocacy group with ties to the Obama administration.