(CNN) -- The U.S.-led war against the Taliban in Afghanistan has been a tough slog, a nearly eight-year conflict replete with gloom.



U.S. Staff Sergeant Robert Brunner secures an area in the Baraki Barak district of Logar Province on August 22.



Lately a lot of the news from Afghanistan seems particularly grim for the United States and its allies.



More U.S. troops have been killed there in August than in any month since the war began. There are indications that more U.S. troops could be deployed to the country.



The Afghan presidential elections this month were rife with charges of fraud. Corruption plagues the political system. The poppy trade is flourishing. And, in the words of the top U.S. military official, Adm. Mike Mullen, the "Taliban insurgency has gotten better, more sophisticated."



Support for the war hit a new low among Americans, a CNN poll found this month.



So why do the United States and its allies continue to pour money and troops into Afghanistan?



"The importance of the place is pretty substantial," said Michael O'Hanlon, senior fellow for foreign policy at the Brookings Institution.



Al Qaeda has used that part of the world as a sanctuary, he said. Neighboring Pakistan has been serious about vanquishing the militants there and that helps the fight against militants in Afghanistan. A victory for al Qaeda in a conflict there would represent an important public relations triumph for the militants, he said.



He understands why Americans are displeased but said people need to feel that progress is being made in the region.



"We haven't been winning for eight years," O'Hanlon said. "They want to know why."



U.S. President Barack Obama has tackled the question head-on.



The al Qaeda and Taliban militants in Afghanistan and Pakistan represent an urgent threat to the United States, he said in March, just as they were when al Qaeda attacked the United States in 2001, when the then-ruling Taliban harbored the terror network.



"Many people in the United States -- and many in partner countries that have sacrificed so much -- have a simple question: What is our purpose in Afghanistan?" the president said.



"After so many years, they ask, why do our men and women still fight and die there? And they deserve a straightforward answer.



"So let me be clear: Al Qaeda and its allies -- the terrorists who planned and supported the 9/11 attacks -- are in Pakistan and Afghanistan.



"Multiple intelligence estimates have warned that al Qaeda is actively planning attacks on the United States homeland from its safe haven in Pakistan. And if the Afghan government falls to the Taliban -- or allows al Qaeda to go unchallenged -- that country will again be a base for terrorists who want to kill as many of our people as they possibly can."



The questions have come up in Britain, too, where the deaths of 15 British troops in July stirred outrage and criticism of Britain's strategy in Afghanistan.



Prime Minister Gordon Brown told his countrymen that British involvement in that country now is as crucial as it was after the 2001 terrorist attacks.



"In 2001 the case for intervention in Afghanistan was to take on a global terrorist threat and prevent terrorist attacks in Britain and across the world," he said. "In 2009 the overriding reason for our continued involvement is the same -- to take on, at its source, the terrorist threat, and prevent attacks here and elsewhere."



Obama said the Afghan insurgency "feeds instability" in Pakistan and Pakistan extremists have the proven ability to undermine the Afghan government. He cited the importance of confronting the heroin trade that finances the insurgency.



Obama has listed several objectives in dealing with Afghanistan and Pakistan, such as promoting an accountable Afghan government and self-reliant security forces, developing a stable government and strong economy in Pakistan, and disrupting terror networks.



Pakistani security forces have been battling militants in the northwestern part of the country, and drone strikes thought to be conducted by the United States have been carried out from Afghanistan against militants in Pakistan.



"The future
who give specific details of this how many deaths what has hit a new low
Barack Obama 15 Support for the war
question: who give specific details of this, answer: Barack Obama | question: how many deaths, answer: 15 | question: what has hit a new low, answer: Support for the war