A profile of the international terrorist network that the United States has singled out as the most serious threat to U.S. security.

The war in Afghanistan hasn't been a major campaign issue even as public support for it has waned. This Backgrounder examines political backing for the war.

The growth and strengthening of Afghanistan's domestic security forces is seen as key to an eventual U.S. exit, but some analysts caution that progress will remain slow.

India's growing economic and political influence in Afghanistan has angered Pakistan, the traditional power there, and has experts worried that Afghanistan could become another battleground in the long-standing rivalry between South Asia's two giants.

International actors are redoubling efforts to restore Afghanistan's agriculture sector and weaken the massive opium trade that helps fund the Taliban. But competing strategies and corruption could stall reforms.

President Obama has made "strategic communications" an essential part of his move to boost the military and nation-building effort in Afghanistan. But experts say countering Taliban messaging will take technology, speed, and demonstrated success in providing security.

The contentious border between Pakistan and Afghanistan remains a site of major conflict, and houses some of the world’s most dangerous militants.

U.S. and Western military officials are calling on Iran to help stabilize Afghanistan, but historic tensions and allegations of arming militants raise doubts about Tehran's intent.

U.S. experts say any new approach to bringing stability to Afghanistan must be regional in scope. Saudi Arabia, with historic ties to the Taliban and Afghan Pashtuns, could hold a principle seat at the table.

As military leaders in Washington revise their war strategy for Afghanistan, analysts say enlisting Afghan tribesmen could aid in security. Others warn that what helped stabilize Iraq may play very differently in the more complex tribal culture of Afghanistan.

Estimates of the total long-term economic costs of the Iraq and Afghanistan wars vary wildly and remain hotly disputed among experts.

Experts warn there is slim hope to control this area given its long history of resisting intervention.

Five years after the U.S.-led invasion, Afghanistan continues to face a number of problems aside from its battle with Taliban fighters and opium farmers.

A rise in drug use in Iran is one overlooked consequence of the surge in opium production in the Taliban-run provinces of southern Afghanistan.

Taliban fighters have stepped up their attacks along the Afghan-Pakistani border as the United States hands over control of southern Afghanistan to NATO forces, freeing up American troops to try, once again, to stem the flow across the frontier.

As NATO prepares to take over military operations in southern Afghanistan from U.S. forces, the Taliban's increasingly bold attacks are straining the political and security framework of the country.

Suicide bombings, once unheard of in Afghanistan, are now on the rise. More than two dozen suicide attacks since parliamentary elections in September 2005 have raised fears that Afghan militants are adopting tactics from insurgencies in Iraq and elsewhere.