The day after a team of U.S. Navy SEALs killed Osama bin Laden in a stealth raid on his compound in Pakistan, the FBI updated its "10 Most Wanted Fugitives" list with one word under bin Laden's undated photo: "Deceased."

But two weeks after the world's most infamous terrorist was buried in the North Arabian Sea, there's a central, lingering question in the sanctums of intelligence and military planning: Who are the new terrorist leaders causing U.S. counterterrorism officials to lose sleep?

One principal figure has long been known to intelligence and national security insiders: U.S.-born, English-speaking propaganda chief of a Yemen-based al Qaeda offshoot, Anwar al-Awlaki. The militant cleric has been implicated in many of the recent high-profile attacks in the United States, from the failed 2010 car bombing in Times Square to the 2009 massacre of 13 U.S. soldiers at Fort Hood, Texas.

But beyond prominent and well known figures such as al-Awlaki, the question of identifying key terrorist targets is a tricky one. In large part, that's because bin Laden himself was striving to sustain al Qaeda, and the Islamist movement more broadly, as a cell-based, leaderless effort that functioned independent of state support--a viral model of terrorist insurgency, in essence.

"The interesting thing going forward is going to be what exactly is bin Laden's legacy," Rick "Ozzie" Nelson, director of counterterrorism and homeland security studies at the Center for Strategic and International Studies, told The Envoy.

"Bin Laden wanted it to be more than an organization; a movement with a 1,000 bin Ladens," said Nelson, a 20-year Navy veteran who previously served at the U.S. National Counter Terrorism Center (NCTC). "He wanted it to be a self-sustaining, self-sufficient movement beyond his leadership."

"It's going to take us a few years to figure out whether his efforts over the last few decades have been successful," Nelson explained. "Was he successful in creating an organization that is self-sustaining, or was it only as big as his persona?"

Indeed, it will take some time to sort out this question within the enormous federal bureaucracy devoted to national security and the global terrorist threat.

Various U.S. government bureaucracies maintain lists of terrorist suspects and entities. The Treasury Department's Office of Foreign Asset Controls maintains a list of "specially designated nationals and blocked persons" with whom U.S. persons and companies are prohibited from conducting business and financial transactions, for instance. Treasury updates that list frequently--so frequently, in fact, that it now runs hundreds of pages long. The State Department meanwhile, keeps lists of designated Foreign Terrorist Organizations, which are banned from receiving material support from U.S. persons and companies. State also keeps a second list of U.S.-designated terrorist individuals and organizations authorized under Executive Order 13224, which former President George W. Bush signed in the wake of the September 11, 2001 terrorist attacks to restrict terrorism financing. Yet a third State document--the Terrorism Exclusion List--monitors terrorist suspects who are forbidden from traveling freely within the United States.

The litany of federal lists follows a rough division of labor among lead agencies, experts say. The State Department list "tends to target [terrorist] operatives, and the Treasury Department [terrorism] financiers, but the rules aren't hard and fast," said Matthew Levitt, a former FBI counterterrorism analyst now with the Washington Institute for Near East Policy.

The more basic problem with the terrorism watch lists, observers say, is a familiar one in Washington: data sprawl. Both the Treasury and State lists have bulked into huge databases that tend to distract, rather than focus, the commitment of personnel and resources, according to a former senior U.S. intelligence official speaking on condition of anonymity.

Policy makers have sought to counteract this risk with a shorter list of top-priority names, which for national security reasons is not made available for public consumption. The Bush administration inaugurated this more operational, frequently tweaked list of "high-value targets"--reportedly numbering between 10 to 30 significant terrorist suspects at any one time --which identifies prime targets for military and intelligence operations to capture or kill.