George W. Bush now has his ace of spades, but what he still covets remains as elusive as ever: the joker in the axis of evil deck, wildcard Osama bin Laden.

During his televised address yesterday, the US President did not directly refer to bin Laden, whose defiance of a superpower's manhunt has elevated the terror mastermind to near mythical status in the Islamic world, beyond pledging that the US would press forward "capture by capture, cell by cell, and victory by victory".

But the architect of this 21st-century holy war between the West, and its allies, and Islamic fundamentalism casts a large and daunting shadow across the Bush presidency and the American psyche.

"The only thing that it would take to make Christmas better for the American soldier," said George Heath, a US army spokesman at Fort Campbell, after Hussein's humiliating demise "(is) if we could find Osama bin Laden. That would be a great Christmas present."

Former CIA counter-intelligence chief Vince Cannistraro said getting bin Laden was "absolutely imperative" for the US because of the inspiration, and direction, he provided al-Qa'ida and its numerous freelance off-shoots.

Mr Cannistraro and several other analysts agreed bin Laden was public enemy number one and of much more strategic importance to the US than Hussein.

The effect of Hussein's downfall seems largely symbolic as he appears to have had no operational role, seemingly having spent his time burrowing into holes to avoid capture, as opposed to bin Laden, who continues plotting worldwide terrorism cabals.

Joseph Cirincione, a fellow at the Carnegie Endowment for International Peace, characterised the dictator's capture as "largely irrelevant in the larger war against terrorism".

"Saddam means nothing to al-Qa'ida and all the al-Qa'ida-like forces," he said.

It is bin Laden who singlehandedly "has bedeviled American efforts on the war against terrorism", Time magazine editor-at-large Michael Elliott wrote yesterday.

"The capture of Saddam helps, but so long as bin Laden remains at large, all the power and high-tech wizardry of the American armed forces are still losing the battle that is most important in the Islamic world - the struggle to convince ordinary Muslims that those who espouse terror and oppose liberal, modern social developments are bound, eventually, to lose."

For more than two years - since the September 11 attacks - the US, with all its considerable resources, has hunted the Saudi-born millionaire. To their eternal regret, the Americans had bin Laden cornered in the Tora Bora caves of Afghanistan in late 2001 but let him slip through their hands.

Realistically, Hussein was always going to be the easier prey. Consider that 130,000 US troops were virtually on top of the longtime Iraqi strongman.

US commanders were convinced - correctly, as it eventuated - that Hussein would return to his stronghold, the region around Tikrit, north of Baghdad, where an alliance of friends and relatives would help him avoid capture. Yet, despite the efforts of thousands of US soldiers on the ground each day and the lure of a $US25million ($34 million) bounty, it still took more than eight months to catch him.

Bin Laden, by contrast, is believed to be based somewhere in remote mountains along an inhospitable 2400km stretch of border between Pakistan and Afghanistan.

The region is under the control of tribal warlords whose customs dictate that guests, even if fugitives, be helped. Those who are not religious zealots - to whom betraying bin Laden would be akin to betraying Islam - have so far been unmotivated by the $US25 million reward.

While getting Hussein in the end was a military operation, James Dunnigan, the author of several books about the military, said the nature of bin Laden's situation meant catching him was "more of a CIA job". "Getting bin Laden consists largely of making deals with Pashtun and Baluchi tribal chiefs, not to mention various Pakistani army and Inter Services Intelligence agency people," he said.

Interestingly, the Pentagon said yesterday it would not rush back to Afghanistan the 600 specialised troops - from linguists to commandos and CIA paramilitary units - pulled from the hunt for bin Laden earlier this year and redirected to Iraq. That could be because the US expects Iraq, with or without Hussein's loyalist Baathists, to become perhaps the primary battleground in the war on terrorism.

They are not alone. Newsweek magazine reported last week that bin Laden had personally ordered that fighters and funds be diverted to Iraq from the Taliban resistance in Afghanistan. Evidence, if any was needed, that the joker remains wild.