Doh, what about bin Laden?

Sen. Bill Nelson, a Florida Democrat, surely didn’t mean to be a spoilsport Thursday when he interrupted all the bipartisan celebration over the killing of Abu Musab al-Zarqawi with an inopportune observation.

What about the man Bush said he wanted “dead or alive” a week after the Sept. 11, 2001 attacks?

“The best news will be when we hear that we’ve taken out Osama bin Laden _ the face of terrorism everywhere,” said Nelson, a member of the Senate Armed Services Committee.

Despite a $25 million bounty on his head and an international manhunt in the mountainous terrain along the Afghanistan-Pakistan border, bin Laden is still on the lam more than 4 1/2 years after his operatives piloted commercial jets into the World Trade Center, the Pentagon and a Pennsylvania field.

Zarqawi’s infamy is of more recent vintage as the Jordanian waged dozens of brutal insurgent attacks in Iraq, even personally beheading Nicholas Berg, an American contractor, in one videotaped execution.

Zarqawi swore allegiance to bin Laden in 2004 and renamed his group al Qaeda in Iraq; bin Laden, in turn, released an audio tape in which he crowned Zarqawi “the prince of al Qaeda in Iraq.”

Tensions later emerged between the two terrorist kingpins. In a letter last October, intercepted by Western intelligence agencies, Ayman al-Zawahiri, the Egyptian-born deputy to bin Laden who is believed to be hiding with the Saudi fugitive, warned Zarqawi that public decapitations might cause a public relations setback.

Just as Bush has made Iraq the central front in the worldwide struggle against terrorism, he was quick to claim that the impact of Zarqawi’s death would be felt beyond Iraq.

“Zarqawi’s death is a severe blow to al Qaeda,” he said. “It’s a victory in the global war on terror, and it is an opportunity for Iraq’s new government to turn the tide of this struggle.”

Asked directly whether Bush believes that Zarqawi’s killing is more significant than the death or capture of bin Laden would be, White House press secretary Tony Snow deferred.

“I wouldn’t compare,” Snow said. “I really wouldn’t. … I think rather than trying to compare people who take delight and believe that they serve a holy mission by slaughtering innocents, I think it’s important that we took one down.”

Terrorism experts, though, said there simply is no comparison: Osama bin Laden is still Public Enemy No. 1.

“It’s a good thing to have gotten Zarqawi, but it doesn’t end the insurgency in Iraq, and it certainly doesn’t bring us any closer to finding bin Laden,” said Charles Pena, author of a new book on terrorism and an analyst with the Coalition for a Realistic Foreign Policy in Washington.

“You’ve got to be in the right place to find bin Laden, and we’re not paying attention to Afghanistan and Pakistan,” Pena said. “A lot of the type of people and units you would want for a manhunt were diverted to Iraq, and a lot of the resources we would need to go after bin Laden aren’t where they need to be.”

Farhana Ali, a Pakistani-born former U.S. intelligence analyst now with the Rand think tank, said that during a visit late last year, she saw many posters of bin Laden in Pakistan’s Northwestern Frontier Province, a hotbed of radical Islam.

“Most Pakistanis reject his use of violence, but they understand it,” Ali said. “In the Iraqi context, the raid against Zarqawi is important, but in terms of the global jihad, it doesn’t matter. But bin Laden’s death would matter in the global jihad landscape. Bin Laden started the entire organization. He has been the symbolic figure for global jihad.”

The inability of U.S. and Pakistani forces to capture bin Laden and Zawahiri, she said, “is very disconcerting to intelligence sources fighting the war on terrorism, and it also continues to provide inspiration” to their followers.

Pena said that Pakistani President Pervez Musharraf is “walking a political tightrope” as he tries to help the United States fight terrorism while not angering Muslim sympathizers of bin Laden.

When Pakistani security forces waged broad sweeps in northwestern Pakistan this week, a senior officer felt compelled to say they weren’t targeting bin Laden.

“He could be anywhere,” Maj. Gen. Shaukat Sultan said. “Our own thinking is that he is still in Afghanistan. We are not into a single manhunt. It is a broad war on terror.”

The U.S. government says it has captured more than 3,000 al Qaeda members since Sept. 11, among them two-thirds of the group’s leaders. The high-profile detainees include Khalid Sheikh Mohammed, planner of the Sept. 11 attacks who was arrested in Pakistan in March 2003, and Abu Zubaydah, a senior field commander captured in Pakistan a year earlier.

Bin Laden is guarded by at least 50 men arranged in concentric circles, according to U.S. and Pakistani intelligence sources. When he and his supporters move, they travel at night dressed in women’s clothing to avoid satellite detection.

Bin Laden reportedly plants land mines and other high explosives around his hideouts when he sleeps, and he has instructed his aides not to allow him to be taken alive.

Russ Tice, a former National Security Agency analyst, said the U.S. government also might not want bin Laden to be captured alive. Bin Laden was allied with anti-Soviet mujihideen backed by the United States in the 1980s.

“Neither we nor those ruling the Arab world would want him alive,” Tice said. “He knows way too much that would be embarrassing to all parties involved.”