But the challenge in Afghanistan is becoming more difficult in the face of gains by the Taliban, rising U.S. casualties, a weak Afghan government widely viewed as corrupt, and a sense among U.S. commanders that they must start the military effort largely from scratch nearly eight years after it began.
A turnaround is crucial because military strategists believe they will not be able to get the additional troops they feel they need in coming months if they fail to show that their new approach is working, U.S. officials and advisors say.
"Over the next 12 to 15 months, among the things you absolutely, positively have to do is persuade a skeptical American public that this can work, that you have a plan and a strategy that is feasible," said Stephen Biddle, a military expert who advises the U.S.-led command in Afghanistan.
A similarly urgent view was voiced by military and diplomatic officials who described the administration's goals and self-imposed deadline during recent interviews in Afghanistan and Washington. Most spoke on condition of anonymity because they are not authorized to comment publicly.
Defense Secretary Robert M. Gates, in an interview last month, first pointed publicly to the need for progress by next year. Since then, the goal has spanned the administration's international diplomatic efforts, its aid program for the Afghan government and its combat strategy.
Unlike during the Bush administration years, when Defense Secretary Donald H. Rumsfeld clashed with other Cabinet members, particularly in the State Department, Gates' assessment appears to be shared by every other major Obama administration player. At the White House, State Department and elsewhere, officials agreed on the need for rapid progress in key areas.
Besides reversing Taliban advances and strengthening the central government, U.S. officials will strive to hold the NATO alliance intact while reshuffling deployments to consolidate gains, especially in the eastern part of the country, near the Pakistani border.
Administration goals in Afghanistan also include stemming government corruption, improving security forces, especially the police, and reducing violence through efforts such as wooing insurgents.
In part, the administration thinking reflects the growing impatience of liberal Democrats with the war. Sen. Russell Feingold of Wisconsin has called for a "flexible timetable" for troop withdrawals, while House Appropriations Committee Chairman David Obey of Wisconsin has warned of funding cuts next spring unless there is significant progress.
A senior administration official said Obey's comment was "a very important signal" to the White House.
Among military commanders, there has been no effort to sugarcoat conditions in Afghanistan.
"We need a fundamental new approach," said one officer, a senior advisor to Army Gen. Stanley A. McChrystal, the newly appointed top commander in Afghanistan.
McChrystal's initial assessment of Afghanistan to Pentagon officials is due soon, in a report expected to be made public in early September.
That report will probably avoid a troop recommendation, but by outlining McChrystal's view of what has gone wrong and his vision for fixing it, officers hope he can make Washington more receptive to a later request for more troops.
"We have to demonstrate we have a clear way ahead, matched with appropriate resources, that is making an impact on the ground," said the officer.
The proportion of Americans who believe it was a mistake to send troops to Afghanistan rose from about 25% in 2007 to 42% this year, according to Gallup surveys. A slight majority of Americans no longer believe the war is worth fighting, according to a Washington Post-ABC survey this month.
August has been the deadliest month for U.S. troops in Afghanistan. A U.S. fighter was killed Friday when his vehicle hit an explosive device in eastern Afghanistan, bringing the number of U.S. military deaths to 45 and exceeding the previous record, set in July. At least 732 U.S. service members have been killed in the Afghanistan war, compared with more than 4,300 killed in the Iraq conflict.
The faltering public support highlights another concern: the U.S. midterm elections next year. Democratic lawmakers fear they may become targets of Republican political attacks over the administration's handling of the war.
In the face of those doubts and time pressures, top Obama administration officials such as James Jones, the national security advisor, have expressed skepticism about the prospects of sending more troops to Afghanistan.
President Obama has committed 21,000 additional troops this year, bringing the U.S. force to 68,000 by the end of the year. But military analysts said that the new strategy being developed in Kabul, the Afghan capital, will require still more troops.
Officers in Afghanistan consider much of the effort of the last eight years wasted, with too few troops deployed, many in the wrong regions and given the wrong orders.
For instance, in Iraq, the military spent between three and nine months on programs to roust militants from cities. In Afghanistan such clearing operations have lasted as little as three weeks.
"Clearing operations aren't about kicking down doors, or even going house to house once," said Kimberly Kagan, a strategist who has advised the military in both Iraq and Afghanistan. "They are about establishing presence and then building a trust relationship with the local population so that over time they feel they can provide information."
Shoring up NATO
Diplomatically, U.S. officials have begun a push to persuade NATO countries to send more forces to Afghanistan. And they are also trying to stave off departures by key allies.
The North Atlantic Treaty Organization, with its 38,000 troops, is considered important both to combat efforts and to the international credibility of the war.
But Canada, which now oversees the southern regional command, is scheduled to pull out its combat troops in 2011, and the Dutch are scheduled to leave next year. A German opposition party, the Free Democrats, this month called for the removal of Germany's 4,500 troops. And in Britain, public support for the war is flagging.
Any departures mean more work for U.S. forces, but are also likely to raise questions at home about why Americans are shouldering so much of the burden of the conflict.
"We cannot afford to re-Americanize the war," said a senior administration official.
As the military is overhauling its priorities, so too is the State Department. Richard C. Holbrooke, the U.S. representative for Afghanistan and Pakistan, has signaled a major push to reduce corruption in the government as soon as the presidential election results are known.
Senior officials are weighing a number of approaches, including, possibly, an international commission to probe corruption cases. The goal is not only to improve Afghans' low regard for their government, but also to reassure Americans that the $2.6 billion a month they are providing is well spent.
U.S. officials acknowledge that the task is not easy. Afghan President Hamid Karzai, expected to win the election, has built political support for his administration through alliances with a number of regional leaders and warlords who face allegations of corruption.
One is his running mate, former Defense Minister Mohammed "Marshal" Fahim, accused of involvement in drug trafficking. U.S. officials have already warned Karzai that they were not happy with the prospect of Fahim as vice president.
Improving the police
Key to both the diplomatic and military strategies is a rapid expansion of the Afghan security forces.
U.S. officials are particularly focused on stepping up police training programs, a key to long-term stability in the country.
Holbrooke describes police training as one of the toughest jobs the allies face, and predicts that success in Afghanistan will depend heavily on whether a skilled force can provide security. But NATO officials continue to report that Afghan police, woefully undertrained in many regions, can't be trusted with many of the most important assignments.
Most military officers believe lasting progress will be years in the making. But they also realize that they only have a few months to add to the perception that they are making headway.
As a result, the military is likely to focus on select goals instead of trying to save the entire country at once. McChrystal has said he plans to focus efforts on securing population centers. That means, at least initially, Taliban outposts that do not threaten significant Afghan cities or villages will not be targeted.
"We have to do triage," Biddle said. "We do not have the resources to stabilize the whole country at once."