For eight years since the attacks of Sept. 11, 2001, the U.S. has focused mostly on Afghanistan's Taliban as an unabashed ally of Al Qaeda.
Now, however, forced to choose between sending more troops in an intensified counterinsurgency campaign against Afghanistan's Taliban or largely maintaining troop levels and using more drone strikes to take out Al Qaeda along the border, U.S. officials must first determine which enemy is the greater priority.
That dilemma is complicated by the recent rise of a Pakistani faction of the Taliban that operates in close proximity with Al Qaeda — even as Al Qaeda has lessened activities with its former Afghan Taliban hosts, according to some administration officials.
U.S. officials face a tough challenge in dissecting the structure and leanings of the militant organizations on both sides of the often indiscernible Afghanistan-Pakistan border, and understanding their murky and evolving ties to Al Qaeda.
"You cannot meaningfully distinguish between Al Qaeda and the co-linked (militant) networks — either in terms of understanding the landscape or crafting a policy response," said Vahid Brown, a researcher at the Combating Terrorism Center at West Point.
"If you think you can kill Al Qaeda leaders, as opposed to doing a broader scale effort against the militant environment, that notion is based on a fundamental misapprehension of the nature of the terrain," said Brown, describing the complexity of the networks along the border and their threat.
With concerns about Pakistani militants growing, an influential faction inside the administration that includes Vice President Joe Biden is pushing for the U.S. to concentrate more on Al Qaeda and less on the Afghan Taliban.
But the push for that strategy butts up against the long-perceived union between Al Qaeda and the Afghan Taliban, ingrained in America's consciousness since the Sept. 11 attacks and the ensuing war in Afghanistan.
The 19 Al Qaeda members behind the hijackings that sent planes into the World Trade Center, the Pentagon and the Pennsylvania countryside plotted their attacks from Taliban-protected safe havens in Afghanistan.
The Afghan Taliban took over Afghanistan in 1996. United in Islamic ideology, they sheltered Osama bin Laden and his Al Qaeda followers. Al Qaeda terrorist training camps flourished openly in the 1990s and the two groups shared weapons, financing and tactics.