WASHINGTON » Six months after President Barack Obama decided to send more forces to Afghanistan, the halting progress in the war has crystallized longstanding tensions within the government over the viability of his plan to turn around the country and begin pulling out by July 2011.

Within the administration, the troubles in clearing out the Taliban from a second-tier region and the elusive loyalties of the Afghan president have prompted anxious discussions about whether the policy can work on the timetable the president has set. Even before the recent setbacks, the military was highly skeptical of setting a date to start withdrawing, but Obama insisted on it as a way to bring to conclusion a war now in its ninth year.

For now, the White House has decided to wait until a review, already scheduled for December, to assess whether the target date can still work. But officials are emphasizing that the July 2011 withdrawal start will be based on conditions in the country, and that the president has yet to decide how quickly troops will be pulled out.

Even if some troops do begin coming home then, the officials said that it may be a small number at first. Given that he has tripled the overall force since taking office, Mr. Obama could still end his term with more forces in Afghanistan than when he began it.

"Things are not looking good," said Bruce O. Riedel, a regional specialist at the Brookings Institution who helped formulate the administration’s first Afghan strategy in early 2009. "There’s not much sign of the turnaround that people were hoping for."

Persistent violence in the southern area around Marjah, which was supposed to be an early showcase of the new counterinsurgency operation, has reinforced doubts in Washington about the current approach—doubts only fueled by President Hamid Karzai’s abrupt dismissal of two security officials widely trusted by the Americans.

As he manages that situation, Gen. Stanley A. McChrystal, the commander in Afghanistan, said last week that operations in the Taliban heartland of Kandahar "will happen more slowly than we originally anticipated."

Other military officers, were more pessimistic.

"If anybody thinks Kandahar will be solved this year," a senior military officer said, "they are kidding themselves."

As a result, some inside the administration are already looking ahead to next year, who like others interviewed spoke on the condition of anonymity to discuss internal conversations.

"There are people who always want to rethink the strategy," said a senior administration official.

The official said skeptics like Vice President Joe Biden, who opposed a new commitment of troops during last fall’s strategy review, favor rethinking the approach, while others who supported more troops, like Gen. David H. Petraeus, want to stay the course.

Other officials said there is no debate for the moment about stepping up the December review and that Biden, among others, was comfortable with waiting until then for a formal reassessment. But they acknowledged the uncertain trend lines, calling it a glass-half-full or half-empty situation, as one put it.

"There’s some evidence that reminds us that this is not going to be a straight line of progress," said a senior official, reflecting the White House view. "It’s probably best described as zigs and zags. Some days, it’s two steps forward, one step back, or one step forward, two steps back."

The strategy faces scrutiny in Washington in coming days. Petraeus and Michele Flournoy, the under secretary of defense for policy, are scheduled to testify Tuesday before the Senate Armed Services Committee and Wednesday before the House Armed Services Committee.

Obama next week will hold a regularly scheduled video conference with his senior civilian and military officials in the region, including Petraeus and McChrystal.

Administration officials will use the opportunities to argue that there is mixed progress and it is too early to draw firm conclusions. They note that not all of the 30,000 additional troops sent by Obama in December have arrived yet.

Pentagon officials said Monday that there were now 93,000 U.S. troops in Afghanistan, going up to 105,000 by the end of summer.

While acknowledging setbacks, administration officials point to positive signs, including Karzai’s recent peace conference intended to lure Taliban figures out of the war and his tripto the volatile south last weekend. They also expressed satisfaction that the Afghan military and the police have stepped up recruitment and retention to meet their 2010 goals.

In his appearance before Congress on Tuesday, Petraeus plans to argue that the United States has spent the past 15 to 18 months "getting the inputs right," meaning not just tripling the number of forces but also reorganizing military and civilian efforts and installing fresh personnel, according to a senior military officer familiar with the testimony.

Now, it will be more possible to produce "outputs," or results, he plans to say, and will remind lawmakers of his prediction that "it would get harder before it would get easier."

At the same time, U.S. officials shared frustration over the failure of NATO allies to produce 450 trainers sought by the administration. The dismissal of the Afghan security officials and reports that Karzai doubts the Americans can win have also soured the mood. But despite frustration with Karzai, administration officials have concluded they have no obvious alternative, despite his erratic behavior.

"As far as I can tell, they have no plan what to do about this," said a senior Democratic congressional aide, who asked not to be identified while sounding critical of the White House. "They tried tough love; that didn’t work. They tried love bombing, and that didn’t work. The thinking now is, we’ll just muddle through. But that’s not a strategy."

On Capitol Hill, lawmakers expressed concern about Afghanistan but diverged on whether the administration should recalibrate its policy.

"This type of warfare is difficult at best," said Rep. Ike Skelton, D-Mo., chairman of the House Armed Services Committee. "At the end of the day, it’s going to be a challenge of governance. Karzai’s a challenge. But you work with what you have."

Rep. Duncan Hunter Jr., a California Republican on the committee, just returned from a visit to Afghanistan, his second time back after serving a seven-month tour there as a Marine captain in 2007.

"They are getting stuff done and weeding through Karzai’s government," Hunter said. "It just takes time and they don’t have the time."

Riedel, the regional specialist, said the administration had few attractive alternatives to its current course. Pouring in more troops is politically infeasible, he said, while pulling out altogether would make the United States vulnerable to a terrorist attack originating in a Taliban-dominated Afghanistan.

"Staying where you are is not attractive, because sooner or later, it means you’ll lose," Riedel said. "Obama inherited a disaster in Afghanistan and he faces the same bad options he faced in 2008."

© 2010 The New York Times Company