On a May visit to Kabul, President Obama said "a negotiated peace" was a key part of his plan to end the Afghan war.

This wasn't surprising. U.S. military commanders have long stressed that the war with the Taliban can't be won militarily.

Yet, by the time Obama spoke, a yearlong effort by U.S. officials to engage key Taliban leaders had already faltered. Interlocutors for Taliban chief Mullah Mohammed Omar - who were set to open a first-time, political office in the Gulf state of Qatar - suspended the process in March. "Qatar is not over as an option, but the chances are considerably less than 50 percent," a senior administration official recently told me.

When he spoke last week about ending the Afghan war, Obama never mentioned the words negotiated peace.

So here's the question: If the Qatar process is in the deep freeze, where's the political strategy for ending the war?

Skeptics will argue there was never any hope that Taliban leaders would meet U.S. and Afghan conditions for a deal. Those include: renouncing al-Qaeda, laying down arms, and agreeing to abide by the Afghan constitution, which guarantees rights for women and minorities.

In the past, I was among those skeptics who thought the talks were pointless. I've changed my mind.

True, the breakdown in Qatar reveals the size of the challenge. The two sides couldn't even succeed at confidence-building measures: The Taliban claim the United States reneged on a pledge to transfer five important Taliban prisoners from Guantanamo to Qatar (in return, the Taliban were supposed to return a U.S. soldier they are holding). U.S. officials say the deal collapsed over the Taliban's refusal to guarantee the men would not leave Qatar and return to the fight in Afghanistan.

Clearly there were more serious problems. The Taliban are deeply split over peace talks. The administration also includes doubters. These talks could backfire, so there's no pressure from the White House to move them forward, especially in election season.

Yet the best time for talks with the Taliban is now.

Why so? Despite substantial military gains by U.S. troops in southern Afghanistan, the Taliban continue fighting, buoyed by their havens in Pakistan.

Administration officials rightly stress the importance of a recent accord with Kabul that provides for U.S. military advisers and trainers after 2014. These officials believe the accord, along with a series of international aid pledges, will convince Afghans they won't be abandoned.

"You can't underestimate the significance of the Strategic Partnership Agreement," says the senior administration official. "They [the Taliban] were living in a fantasy that after Dec. 31, we'd be gone."

Yet, despite these commitments, Afghan ethnic groups that fought the Taliban in the 1990s are arming for battle. The reason? They aren't certain that the military gains will hold or that Western governments will keep their pledges.

Without a political agreement before 2014, Afghanistan could plunge into civil war.

That prospect also alarms some Taliban leaders, says Pakistani author Ahmed Rashid, a leading expert on the Taliban movement. "The Taliban know they can't win an ethnic civil war," says Rashid, especially since Afghanistan's neighbors will back different factions. The fear of another brutal civil war like the one in the 1990s is what has focused some Taliban leaders on peace talks.

What form those talks should take is under debate within the administration.

"There will be no negotiated deal with Mullah Omar," I was told by the outgoing ambassador to Kabul, Ryan Crocker, in a phone interview. "It wouldn't work here in Afghanistan. You have a fractured, divided Taliban." He added, "I'm not sure we need a Qatar office."

Crocker believes the best approach is to peel off a significant number of Taliban leaders willing to reconcile with the Afghan government. "We can get it [a deal] by onesies and twosies, not some kind of grand bargain with Mullah Omar."

Senior U.S. and Afghan officials view Agha Jan Motasim, a onetime top Taliban leader close to Mullah Omar, as someone "around whom you could organize a group of peace-minded Taliban." That's if he lives long enough to do so.

Motasim, who supports talks with the Americans, was shot and nearly killed in Karachi, Pakistan, probably by Taliban hard-liners; he now lives in Turkey. He believes the Taliban must work with other groups and parties in Afghanistan, not pursue a return to power. Now that Motasim's name has been taken off a United Nations terrorist list, U.S. officials are likely to beat a path to his door.

Administration officials also believe that, as 2014 approaches, the Taliban may be more willing to bargain directly with Afghans. (Until now, the Afghan government's many private meetings with Taliban reps have led nowhere; the militants insist on negotiating first with the Americans.)

"Pay attention to Kyoto," Crocker told me, a reference to a recent peace conference in Japan where an active Taliban leader sat with a senior Afghan government peace negotiator, Masoom Stanekzai. This was the first such meeting in public (although the Taliban made no commitment there to any negotiations).

U.S. officials are also hopeful the Karzai government will finally recognize the need to address the concerns - and fears - of all Afghan factions in any talks with the Taliban.

Will talks with individual Taliban leaders or Afghan-to-Afghan contacts be sufficient to advance a peace process? Uncertain. Probably unlikely. But any negotiating strategy will require a strong push from the White House, and timing is crucial as the 2014 deadline approaches.

"The shorter the time for negotiations, the more dangerous it becomes," Rashid warns gloomily. "If the talks remain frozen, there will be a civil war."

E-mail Trudy Rubin at trubin@phillynews.com.