Fresh reminders of the unsuccessful search come as intelligence officials indicated this week that bin Laden has been in contact with Abu Musab al-Zarqawi, the top al Qaeda figure in Iraq, enlisting his help in planning attacks inside the United States.
Current and former government officials say there is no doubt that the Bush administration wants bin Laden "dead or alive," as the president said shortly after Sept. 11, 2001. But skills and dollars may fall short of desire.
Army Gen. John Abizaid, chief of U.S. Central Command, told the Senate Armed Services Committee this week that bin Laden and the al Qaeda senior leadership have been "our priority target" since Sept. 11 but added, "It's important for all of us to know that military forces do best in attacking the network as opposed to looking for a specific person."
Pakistan's President Gen. Pervez Musharraf said in December 2004 "the trail has gone cold," and U.S. officials largely agree.
Bin Laden is believed to have evaded capture first during the 2001 battle of Tora Bora in Afghanistan and then by hiding along the Afghan-Pakistani border with his top deputy and a circle of supporters protecting him at all costs. Some experts believe he may also be spending time in Pakistani cities.
U.S. personnel including CIA paramilitary, contractors and some of the military's highly trained special forces have been on the hunt. In a recent report, the Congressional Research Service said 18,000 U.S. forces remain in Afghanistan, running down al Qaeda and Taliban, joined by thousands of Pakistani forces and agents.
Yet a former intelligence official, speaking on condition of anonymity, wondered about recent decisions on U.S. resources. The official said intelligence and military assets were moved from Afghanistan to Iraq for the Jan. 30 elections there, and it's unclear whether they went back.
Asked to confirm the shift, Pentagon spokesman Lt. Col. Barry Venable said, "As a matter of security, we don't comment on operational matters."
The Pentagon consumes roughly 80 percent of the classified intelligence budget, estimated at $40 billion.
The No. 2 commander in Afghanistan, Maj. Gen. Eric Olson, recently said he was concerned that U.S. policy-makers will seize on an apparent drop in militant attacks to cut coalition troops to ease the pressure on forces stretched by their deployment in Iraq. Olson added that he did not anticipate any letup in the mission to find bin Laden.
Since the late 1990s, the government has debated how best to get the terror leader and what his capture is worth. In the 2001 Patriot Act, lawmakers authorized the State Department, through its Rewards for Justice Program, to pay more than $5 million.
In November, Congress authorized increasing the reward for information leading to bin Laden's killing or capture to $50 million. But Secretary of State Condoleezza Rice hasn't boosted the reward.
State Department spokesman Lou Fintor said officials are constantly assessing the success of their efforts. "There are no plans at this time to raise the reward. It is at the discretion of the secretary," he said.
Rep. Mark Kirk, R-Ill., who was behind the most recent rewards legislation, said the department is moving fast — "for the normal speed limit at the State Department" — in its consideration of the November legislation.
Kirk applauded other efforts under way, including a recent television, newspaper and radio campaign in four languages to remind Pakistanis about the reward. He was responsible for this legislation too.
Kirk advises patience. On a trip to Pakistan in January, when newspaper ads were running, he said U.S. officials were getting a dozen tips a day on al Qaeda's leadership — up from zero.
James Pavitt, head of the CIA's clandestine service until last summer, said he supports putting anything on the table to find bin Laden.
"That said, for the most part, it is hard for you and me to comprehend what that sort of money is," Pavitt said. "Imagine what it would be for the person in a position to give the tip. Would they be in the position to know the difference between $1 million, $5 million, $10 million?"
While the symbolic importance of capturing bin Laden remains high, Pavitt also stressed the importance of going after the network. "The issue is a network, and it is a network that is more diffuse than it was three-and-half years ago," he said.
Meanwhile, bin Laden continues to operate. He released a video addressed to the American people days before the November elections, appearing healthy, shaven and lit by studio lights.
Within the last several weeks, U.S. officials say bin Laden has been in contact with al-Zarqawi, who first pledged his loyalty to bin Laden in October. Al-Zarqawi is believed to run his own network in Iraq — aligned with al Qaeda and receptive to its cause but maintaining some autonomy.
Yet Vince Cannistraro, former head of the CIA's counterterrorism center, said the message may be good news: "If you've got to go to Zarqawi to ask him to do operations in the U.S., that sounds pretty desperate."