And then there was one. The capture of Saddam Hussein throws the spotlight on the world's other most wanted man, the elusive Osama bin Laden.
The leader of al-Qaida and suspected architect of the September 11, 2001, attacks on New York and Washington could remain at liberty for much longer as difficult Afghan terrain, friendly tribes, a deep well of loyalty and his role as an ideological inspiration all combine to protect him.
"Saddam is no longer a problem now, so bin Laden is the focus," U.S. Ambassador to Afghanistan Zalmay Khalilzad said.
Many analysts argue that with bin Laden still free and possibly planning more attacks on U.S. soil and elsewhere, including perhaps in Iraq itself, he poses a far more potent threat than the former Iraqi leader.
"The single biggest weakness of the U.S. has been the failure to target and neutralize Osama bin Laden and Ayman al-Zawahiri," said terrorism expert Rohan Gunaratna, referring to the al-Qaida chief's Egyptian deputy.
Capturing bin Laden presents a much more formidable challenge to U.S. troops and intelligence, analysts say.
"Unlike Saddam Hussein, Osama bin Laden is not viewed as a tyrant who has butchered many people around him," said Husain Haqqani of the Carnegie Endowment in Washington. "Saddam was in a circle with room for betrayal but there are very few such in the Osama circle.
"And he has local support, he is like a fish swimming in favorable waters," said Haqqani.
That is one of several critical factors that analysts say have helped bin Laden evade the manhunt.
"For more than 10 years, Osama has lived along the Afghan-Pakistan border and enjoys significant support there," said Gunaratna, author of "Inside al-Qaida: Global Network of Terror".
"The Americans have not done anything for these people and they see Osama as their hero and they will protect him," he said.
Fierce defenders
Protecting a guest is a way of life in the ancient honor code of the Pashtun tribes that populate the region where bin Laden is believed to have taken refuge.
"Anyone who handed over Osama bin Laden would be seen as a traitor in the Muslim world," said counter-terror expert Clive Williams of the Australian National University in Canberra. "They would rather be prepared to martyr themselves."
In addition to the loyalty of people in the region, bin Laden is operating in terrain so rugged and mountainous that it provides a natural barrier against those searching for him.
"Saddam Hussein was totally isolated in a country effectively under U.S. control while Osama has the advantage of having people on both sides of the border," said Haqqani.
"There are warlords and local commanders on the Afghan side and possibly low-level government functionaries on the Pakistan side who are ideologically sympathetic," he said.
Also, analysts noted the lure of the militant Islamic ideology that martyrs would be rewarded in the afterlife, compared with Saddam's vehemently secular Baath party.
Such differences are crucial, they said.
Saddam was no guerrilla fighter with an organized clandestine network of agents and safe houses like al-Qaida, said Ahmed Rashid, a Pakistani expert on Afghanistan and author of a book on the Taliban.
"Saddam's capture was a question of intelligence," said Rashid, adding that the chances of someone approaching the U.S. forces with intelligence about bin Laden were remote.
'Their honor is more important'
"This entire region is hostile to the Americans and hostile to the Pakistani government," he said. That reduces the attraction of the $25 million reward on bin Laden's head.
"For the Afghans, their honor is more important," said Gunaratna. "Money is a just a green piece of paper."
While some analysts say elements of Pakistan's military Inter Services Intelligence may be sympathetic to bin Laden, others cite signs that Pakistan is already tracking down those protecting him if he is hiding in the lawless border tribal regions.
"What we are seeing is that Pakistan is investing more resources in developing intelligence on that border, but it is a very long border," said Gunaratna of the highly porous 2,450-km (1,500-mile) frontier with Afghanistan.
Analysts say Pakistan is eager to cooperate with U.S. forces in tracking down members of al-Qaida to boost relations with the United States.
Since the September 11 attacks, some 460 al-Qaida members, including several top leaders, have been arrested in Pakistan.
But Washington has not given the hunt for bin Laden the importance that it could have, analysts said.
It has devoted limited resources to Afghanistan, with only 12,000 troops based in the rugged, landlocked country compared with more than 10 times that number in Iraq.
"Afghanistan is a forgotten war and it is a mistake not to pay attention to it," said Haqqani, adding that U.S. interest evaporated with the overthrow of the Taliban and the apparent dispersal of al-Qaida's leadership in November 2001.
"The Americans need to put resources and men on the ground. That is an absolute necessity," Haqqani said.
