Try as he may, Defense Secretary Donald Rumsfeld cannot seem to shake the dreaded "OBL" question - even coming from his wife, Joyce.
"Every once in a while ... as I get up about 5 o'clock and get ready to take a shower and head for the office, she says, 'Don, where is he?' " Mr. Rumsfeld told a military gathering last week. "I tell her that if I want to bring up Osama bin Laden, I'll wake her up and bring it up myself," he quipped.
Exactly 146 days after the US military launched its war on terrorism, the man most wanted by President Bush as the "evil-doer" behind the Sept. 11 terrorist attacks remains at large - a fact that the Pentagon is working hard to downplay.
Most Americans consider tracking down bin Laden as essential for the success of the Afghanistan campaign, recent polls show.
Indeed, a November poll showed that 60 percent of Americans were willing to risk large numbers of casualties among US troops in order to capture or kill bin Laden.
Yet since the US-led siege at the Tora Bora
cave complex in eastern Afghanistan in December turned up no trace of the Al Qaeda terrorist leader, top Pentagon officials have increasingly argued that - alive or dead - he is irrelevant.
"Everybody wants to know where Osama bin Laden is. The next question is, who cares?" says one Defense Department official, reflecting an attitude widespread in Pentagon corridors.
"Osama bin Laden as a center of gravity is gone," he says.
Indeed, a top US military official this week stated that finding the Saudi-born militant is not even one of the top priorities of the US war on terrorism.
"I wouldn't call it [getting bin Laden] a prime mission," said Joint Chiefs of Staff Chairman Gen. Richard Myers.
On one hand, the Pentagon's message is aimed at convincing Americans that the fight against global terrorist organizations is about much more than pursuing one man. Bringing bin Laden to justice - while important - would not allow America to breathe easy, officials stress.
"He could walk in here tomorrow and Al Qaeda would go on functioning," says Rumsfeld. If alive, bin Laden is busy hiding, cut off from his network and unable to recruit, raise money, or run more terrorist operations, he says.
Instead, it is likely that any future Al Qaeda attacks will be pre-planned acts carried out by some of bin Laden's lieutenants, along with the thousands of trained terrorists at large in cells in dozens of countries around the world.
Gauging the war's success
At the same time, the Pentagon wants to persuade Americans that finding bin Laden is a difficult job, and one that is not a good gauge of the success of the military campaign on terrorism launched Oct. 7.
"Osama bin Laden is a poor measure of effectiveness," says one Defense official.
The United States military, Rumsfeld points out, is organized, equipped, and trained to fight foreign armies - not to conduct manhunts.
While accepting the task of tracking bin Laden down as something US forces "have to do," he admits that the military is still grappling for strategies, "trying to figure out different ways of doing it."
As for the status of the search today, all the Pentagon can say with certainty is that it has not received hard intelligence for some time indicating that bin Laden is alive.
At least three top Pentagon officials - Rumsfeld, Deputy Defense Secretary Paul Wolfowitz, and General Myers - have suggested in the past week that, if alive, bin Laden is most likely either in Afghanistan or near the Afghan border in Pakistan. "But that's very circumstantial evidence," Mr. Wolfowitz said.
Yet the Pentagon has also left open the possibility that bin Laden was among the three suspected Al Qaeda members killed on Feb. 4 in a Hellfire missile strike by a CIA-guided Predator drone, on a hillside in the vicinity of Zhawar Kili in Afghanistan.
The DNA of those killed has been brought back to the United States for examination and possible matching against DNA from bin Laden's relatives.
On Wednesday, Gen. Peter Pace, vice chairman of the Joint Chiefs of Staff, said "it would surprise me if we hadn't" asked for DNA samples from bin Laden family members.
The video, taken by the Predator drone, tracked a group of 15 or 20 people apparently convening for a meeting, say Pentagon officials who watched the footage.
Myers said the video showed clearly the size of the people, their actions, as well as "deference paid," apparently to senior members of the group.
Rumsfeld said the group was moving among outcroppings of rocks and trees, and appeared to be aware the Predator drone was in the vicinity.
He dismissed as "ludicrous" reports from local Afghans that the people killed by the missile were scrap-metal collectors.
Credit-card applications and airline schedules were found among the debris from the strike, as well as ammunition, officials say.
Asked in a television interview on Sunday whether bin Laden might have been among those killed, Rumsfeld replied "I just don't know."