Soon after the Taliban’s fall, the State Department sent one of its most intrepid diplomats, Ryan Crocker, to reopen the U.S. Embassy in Kabul.

He had already served as ambassador to Kuwait, Lebanon, and Syria; he went on to serve in Pakistan, and in Iraq during the “surge.” He then retired and was enjoying a deanship at Texas A&M University. But President Obama asked him to return to Kabul a year ago, and Crocker thought he could not refuse.

This month, the 63-year-old Crocker will retire again, this time for health reasons, leaving Kabul in a crucial period of transition as the United States prepares to withdraw most of its troops by the end of 2014. I spoke to him by phone last week about what he has achieved and Afghanistan’s future.

“There is every chance” that some U.S. troops will remain as advisers after 2014, he told me. He stressed that continued U.S. economic and military aid will be essential to keep Afghanistan stable after our troop drawdown. He also said that there will not be “some kind of grand bargain with (Taliban leader) Mullah Omar” to stop the Afghan fighting, but that the Afghan government can win over individual Taliban leaders.

But first, the ambassador wanted to talk about the invaluable work that U.S. civilians have done on the war front.

Crocker presided over a surge of U.S. civilian personnel aimed at helping Afghan officials deliver better governance. He bristles at claims (mine included) that diplomats and aid workers are cut off from their Afghan counterparts, or have failed to make a difference.

“When I first got here in January 2002,” Crocker says, “nine percent of Afghans had access to health care. There were 20,000 mobile phones. Now there are 16 million mobile subscribers and more than 60 percent of Afghans live within an hour’s walk of health care.

“The number of students is up to eight million in a decade. We increased life expectancy by a decade in the last nine years. This is not nothing.“

Crocker says he made an immediate effort in 2011 to ”get the right people in the right places.“ He says his civilian staff regularly travels “outside the wire” to visit Afghan counterparts and inspect projects.

Some observers say the State Department needs a special corps of experienced officers for combat zones who would serve longer tours and have advanced language training. Crocker says such a corps “is already happening” through self-selection. Many civilians now stay longer or serve multiple tours.

“I have one person on her eighth year,” he says, referring to Deborah Alexander, who has served as a liaison with military colleagues in many provinces. She has lived in tents, a mud hut and a shipping container, and worked with Afghans ranging from provincial governors to village women. Others join up as civilians after military tours in Afghanistan or Iraq.

Of course, many observers question whether economically pinched Western governments will continue aiding a corrupt Afghan government after 2014. Crocker warns what would happen after an aid cutoff: “Afghanistan collapsed after the Soviet withdrawal (in 1989) when the money stopped. No one wants to see history repeat itself. If we have to ante up a little more than intended, it is still pretty cheap insurance.”

The ambassador had just returned from Tokyo, where an international donor’s conference pledged $16 billion for Afghan economic development over the next four years. “Read the Tokyo document,” Crocker advised. It requires the Afghan government to reduce corruption before receiving all of the money. He insists that “there is a chance for improvement on corruption,” but it’s a long-term project.

One of Crocker’s major achievements was a strategic partnership agreement that opens the door for a limited number of U.S. forces after 2014 — details to be negotiated. “I think there is every chance that post-2014 we will continue to have a presence here,” Crocker says, “certainly to advise and assist.”

Crocker stressed the importance of a recent encounter at a peace forum in Kyoto, Japan, between a high-ranking Taliban and a senior adviser to Karzai. He says the Taliban will eventually have to bargain with Kabul, not with the Americans.

“We haven’t talked to the Taliban in months,” he noted. “It has to be an Afghan deal.”