The Taliban may have reached the peak of their military achievements in the war in Afghanistan, one of the world's top authorities on the Taliban said.

And that position of relative strength might make them more amenable to talks, Pakistani journalist and author Ahmed Rashid said in an interview Monday with CNN's Christiane Amanpour.

"They can't go much further than where they are now," Rashid said. "They're across the country. They're having shadow governors and shadow government in all the major provinces, but they can't take the cities because of NATO firepower. They can't create a populist movement against the Americans. They tried and failed to do that."

"So in a way," Rashid added, "the Taliban are in a very strong position, which actually might make them more amenable for talks right now."

His comments came as Afghan President Hamid Karzai stepped up his efforts to reconcile with Taliban fighters and reintegrate them with Afghan society. In Kabul on Sunday, Karzai said, "The Taliban are welcome to return to their own country and work for peace in order for us to be able then to have the U.S. and other forces have the freedom to go back home."

Karzai was renewing an appeal he made at the London Conference on Afghanistan last week. At the conference, Afghanistan and world powers agreed to establish a $500 million "pay-for-peace" fund to try to convince rank-and-file Taliban members to give up the fight, even as the U.S. and its allies send more than 30,000 additional troops to the country -- the so-called "surge."

Georgetown University's Christine Fair, who has analyzed Taliban suicide attacks in Afghanistan for the U.N., agreed with Rashid's assessment and said now is the time to offer them an opportunity for reconciliation.

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"The surge is really focusing on controlling major urban populations, so from the point of view of the Taliban this is going to be an ideal time for them to try to reach some deal," she said. "And to be very clear, I support reconciliation. My concern is that the reintegration plan doesn't go far enough."

She said that to be successful, reintegration requires more than just financial incentives. "You also need political incentives to bring them into the picture," she added.

Alex Thier, director for Afghanistan and Pakistan at the U.S. Institute of Peace, was more cautious about the possibility of convincing the Taliban to strike some kind of deal with the Karzai government.

"They are not particularly amenable to compromise. So while I agree that the Taliban in some ways may be reaching the height of their power, I'm not sure that they know that," he said.

"They've demonstrated repeatedly that they are willing to press ahead in the face of uncertainty and danger, as they did during the civil war when it was far from clear that they would achieve what they did," he added. "And of course, after September 11, they were in some ways offered to keep Afghanistan if they turned over Bin Laden, and they refused to, and lost it all."

There are also concerns among Afghanistan's ethnic minorities about doing any kind of deal with the Taliban, Thier said, adding. "They (ethnic minorities) certainly have the power to end that prospect."

Fair emphasized the importance of making the peace effort an Afghan process. "What the United States should actually do is really be thinking about Plan B," she said.

"What are our interests in Afghanistan? Should we be looking for ways to protect ourselves against al Qaeda? Should we be looking at the possibility that Pakistan becomes the locus of our security interests?"

Fair said that in her opinion, at some point the Taliban will return to Kabul, so it's important for the U.S. to be thinking about its national interest in light of that potential reality.

(CNN)