Analysis and commentary are my bread and my butter. But detached perspective is in short supply when it comes to Khalid Sheik Mohammed. I hate this murdering terrorist chieftain even for being captured.

Why? Because the news of the capture of al Qaeda's No. 3 in Pakistan stirs up the raw memories of the pain, suffering and dread of 9/11 -- and a spasm of self-reproach for not recalling directly what that day was like more often than I do. Worse: more often than I promised myself I would. It is like treading on a live electric wire after stepping over it for much of the past 18 months.

There is a song I avoid playing when I don't want to risk tears rolling down my cheeks. For me, Bruce Springsteen captures both the anger and the consolation of time passing since that "Lonesome Day":

House is on fire,

Viper's in the grass,

A little revenge and

This too shall pass.

I put the Boss's album on the instant I heard of the capture. And listened and hoped that the day of lawful, judicious revenge does not pass too quickly for this man known as Mohammed.

The capture of this particular viper may well be even more important than nabbing or killing Osama bin Laden, both in solving the mysteries of 9/11 and in reaching the tipping point in the war on terrorism.

Long years of interviewing Middle East terrorist leaders and my reading of human nature suggest this: It is one thing to give up your life to the delusion of advancing a glorious cause toward victory and the final removal of evil. It is quite another, much harder thing to sacrifice yourself to a losing cause in full retreat.

There is no scientific way of knowing where that tipping point is. But that it exists is shown by the cyclical pattern of terrorism through the ages. Civilization can never rid itself of murdering fanatics. But it can disrupt, disband and contain their operations, and organize defenses against them. The capture of Mohammed is a big step forward.

He knows the answer to these two central questions: How did al Qaeda, within two or three years, go from obscurity to becoming super-terrorists capable of blowing up U.S. embassies, warships and skyscrapers with astonishing precision? And what are the links between 9/11 and the bombing of the World Trade Center in 1993 by Ramzi Yousef, who authorities say is Mohammed's nephew?

The captured viper also knows the answer to another question that should not be rushed past just because it is obvious: Why did he choose to hide in Rawalpindi, which is the headquarters of Pakistan's military and Inter-Service Intelligence agency, and which is immediately adjacent to the Pakistani diplomatic capital of Islamabad, where Ramzi Yousef was captured in 1995?

The U.S. media and government officials describe Mohammed and Yousef as "masters of disguise," and then assume they are who they say they are this time. There is scant reason to be so trusting. When Judge Kevin Thomas Duffy sentenced Yousef to life plus 240 years in 1998, he said: "We don't even know what your real name is."

Why two men from the remote and ungoverned Pakistani province of Baluchistan who grew up in Kuwait would devote their lives to killing Americans is a mystery. How they acquired prodigious masterminding skills and, at least in Mohammed's case, rabid Islamic fanaticism after lives of intellectual mediocrity and pleasure-seeking, also is a mystery. So is their connection, if any, to al Qaeda at the time of the first World Trade Center bombing. So is their instinctive flight in extremis to the power centers of Pakistan.

Mohammed migrated from the identity of small-time freelance terrorist to the top ranks of bin Laden's ultra-secretive band not long after the 1993 bombing resulted in the breakup of Yousef's U.S. network. Could al Qaeda have been the target of a takeover operation by an intelligence service with good legend-manufacturing skills and a great, burning desire for revenge on the United States?

That is a question U.S. investigators should push more actively. In "Study of Revenge," author Laurie Mylroie sketches the strong ties that Iraq's intelligence services have developed in Pakistani Baluchistan. And the Iraqi Embassy in Islamabad has been publicly identified by Secretary of State Colin Powell as a center for contact with al Qaeda.

Why did the two master terrorists get chased to earth a handful of miles from that embassy? The answer to the 9/11 mysteries may be hiding in plain sight.