Maj. Gen. James C. McConville gives a pep talk to soldiers from the 10th Mountain Division at Camp Clark in Khost Province in Afghanistan on Dec. 14. (Nikki Kahn/The Washington Post)

Across Afghanistan, a once massive network of U.S. military installations has been largely dismantled, shifting the burden of America’s longest war to Afghan troops who are anxiously awaiting the resolution of a dispute between their president and Washington.

In the few dozen bases that remain, including this dusty camp in the east, U.S. troops are racing to improve the Afghan army’s logistics and supply systems ahead of a year that many see as the war’s turning point.

“The enemy used to say they were fighting foreign occupiers,” Maj. Gen. James C. McConville, commander of U.S. forces in eastern Afghanistan, told troops deployed here during a recent visit. “They can’t say that anymore. They’re fighting Afghans.”

That the Afghan army is fighting is not in dispute. But its odds of success are uncertain in the face of a resilient insurgency and the increasingly bitter relationship between Afghan President Hamid Karzai and Washington, the Afghan government’s chief benefactor. Karzai has balked at signing a bilateral pact that would keep a small, U.S.-led foreign military contingent here beyond 2014, and that has jeopardized the billions of dollars Western nations have pledged to spend here in the years ahead.

“For now, our army can take care of the country,” said 1st Lt. Hamed Hamdan, an officer working alongside U.S. troops in Khost province, which shares a border with Pakistan and serves as a gateway to Kabul. “But we won’t be able to take care of our country without the coalition troops. All the supplies we have come from America — fuel, ammunition, everything. We are a new army.”

To a large extent, Afghan troops have exceeded expectations this year as the American drawdown has accelerated.

Shortly after McConville took command of U.S. forces in the east, Afghan military leaders embarked on an ambitious effort to gain control of rural Taliban strongholds, including parts of the Korangal Valley, which for years had bedeviled American forces. The objective troubled U.S. commanders, who were advising the Afghans to focus on the country’s main urban areas and key roadways.

“I was, quite frankly, concerned,” McConville said in an interview aboard a Black Hawk helicopter as it zipped over the rugged, snow-capped terrain that has made this region a challenging battleground for centuries. “This is not where the decisive population is, and I was concerned about the Afghans over-stretching their capacities.”

To his surprise, McConville said, the Afghans made significant inroads, even managing to secure a foothold in Wanat, a village where a U.S. patrol base was overrun by Taliban militants in 2008, leaving nine American soldiers dead.

“I was very proud of them,” the general said. “They defeated the enemy in Wanat and are holding the area with the Afghan police to this day.”

As the U.S. presence in the east has thinned out, the general said, Afghan security forces have found ways to coexist with insurgents, a dynamic that he anticipates could expand in the months ahead. Those deals reflect what McConville sees as the reality: A decisive military victory is not within reach.

“I think there will be some sort of accommodation at the local level as people realize that the way ahead is not killing each other,” said the general, who commands the 101st Airborne Division. “I don’t think the enemies of Afghanistan will be defeated in the battlefield. They will be defeated when they realize that there is no future in what they’re doing, which is killing innocent people.”

Some Afghans worry that the country’s forces are the ones that could be defeated in the coming year. Hayatullah Hassady, 22, a military interpreter who works at Camp Clark, said he has seen his countrymen in uniform become increasingly confident and competent over the past few years. But they continue to depend on the American forces for basic supplies and have grown deeply anxious about the prospect of a sudden U.S. military pullout.

“If the Americans leave, within three months the ANA will be broken,” he said, using the acronym for the Afghan National Army. “Everyone is talking about that right now, everyone is thinking about their future.”

During a recent visit to Afghanistan, Secretary of Defense Chuck Hagel heard from senior Afghan commanders who expressed similar concerns. One told the Pentagon chief that if the Americans were to leave hastily, “tomorrow there would be fighting in the streets of Kabul,” a senior U.S. defense official told reporters, speaking on the condition of anonymity to describe private meetings.

U.S. officials are hoping that they will manage to strike a deal with Karzai’s government soon.

“There’s a recognition that the foundation is very precarious and could be undone,” the official said.

Frustration with Karzai is growing among uniformed Afghans of all ranks, who in recent weeks have taken the unusual step of criticizing their commander in chief. Hamdan, the Afghan lieutenant, said he believed senior officials in Kabul siphon off much of the money Washington and its allies spend in Afghanistan.

“We have a presidential office that operates corruptly,” he said. “You can’t trust anyone.”