Anyone paying attention to the Zacarias Moussaoui trial gets it now. All the 9/11 blanks are filled in, and the picture is complete. Sorry, conspiracy freaks and blind partisan hacks. Dull, common, gross incompetence is again at the heart of a deadly government cluster-hump.

Do not linger on Moussaoui’s bizarre suicide-by-testimony or the literal cheerleading for his execution—he knew. He lied. And 2,749 people died.

Neither of these is the real story of this case. Rather, the story is the definitive proof Moussaoui’s case provides that the US government—pre-PATRIOT Act, pre-NSA wiretaps and all—had and missed clear opportunities to stop 9/11. The FBI uniquely and repeatedly punted carefully gathered evidence of an attack in favor of adherence to bureaucratic hierarchies and power trips.

The testimony of FBI agent Harry Samit forever buries the quaint notion that 9/11 was unforeseen and unpreventable. Beginning with Moussaoui’s August 16, 2001 arrest, Samit mounted a global  investigation of the man and concluded that an attack involving hijacked airplanes was imminent.

The flipside of Samit is Michael Rolince, former head of the FBI’s International Terrorism Operations Section. Rolince is the man who previously deflected questions about the FBI’s pursuit, or lack thereof, of pre-9/11 terror suspects with the line, “Would CNN have really aired their photos if we’d asked them?”

Rolince smugly insisted at trial that Samit’s “suppositions, hunches and suspicions were one thing and what we knew” was another. Yet Rolince, in service of the government’s desire to link Moussaoui to 9/11 and trigger the death penalty, also tried to argue that, had Moussaoui spilled his guts, everything would have changed. 9/11 might have been prevented. In short, Samit’s investigation and leads were not enough; Moussaoui had to speak up for the FBI brass to hear anything.

• • •

When defense lawyer Edward MacMahon cross-examined Rolince, possibly the first and only time a government security official has been so challenged on 9/11, the disconnect between the official story and reality was plain. Rolince knew nothing of the Aug. 18, 2001 memo Samit had sent to his office warning of terror links. In that memo, Samit warned that Moussaoui wanted to hijack a plane and had the weapons to do it. Samit also warned that Moussaoui “believes it is acceptable to kill civilians.” Rolince testified he never read the memo.

On August 17 Samit sent an e-mail to his direct superiors at FBI headquarters recounting Moussaoui’s training on 747 simulators. “His excuse is weak, he just wants to learn how to do it... That’s pretty ominous and obviously suggests some sort of hijacking plan,” Samit wrote.

Rebuffed by his superiors and ignored by Rolince, Samit still sought out more info from sources as diverse as the FBI’s London, Paris, and Oklahoma City offices, the CIA’s counterterrorism center, the Secret Service, the Immigration and Naturalization Service, and the Federal Aviation Administration.

He was sufficiently alarmed by what he heard that Samit sent an Aug. 21 e-mail asking that the Secret Service be informed about Moussaoui’s intentions to see the White House and that he was interested in flight training.

Samit testified that on Aug. 22 he had learned from the French—the French!—that Moussaoui had recruited a fighter to go to Chechnya in 2000 to fight with Islamic radicals with previous links, so the CIA told Samit, to Osama bin Laden. The FBI brass remained unmoved.

Defense attorney MacMahon then displayed an Aug. 30, 2001 communication addressed to Samit and FBI headquarters agent Mike Maltbie from a Bureau agent in Paris. It passed along that French intelligence thought Moussaoui was “very dangerous” and had soaked up radical views at London’s infamous Finnsbury Park mosque. The French also said Moussaoui was “completely devoted” to bin Laden-style jihadism and, significantly, had traveled to Afghanistan.

Yet on Aug. 31 Maltbie stopped Samit from sending a letter to the FAA in Washington advising them of “a potential threat to security of commercial aircraft” based on the Moussaoui case.

“Minneapolis believes Moussaoui, [Moussaoui’s roommate Hussein] Al Attas and others not yet known were...engaged in preparing to seize 747s,” the aborted warning said.

• • •

Samit did directly tell FAA officials in Minneapolis of his concerns on Sept. 5.

In total, the information Samit pulled together dovetailed with his belief that, based on interviews with the suspect, Moussaoui had been to Afghan terror training camps.

The 9/11 Commission investigation detailed that British intelligence directly told US officials on September 13, 2001, that Moussaoui had attended a training camp in Afghanistan.

“Had this information been available in late August 2001, the Moussaoui case would almost certainly have received intense, high-level attention,” the commission concluded. As it turns out, Samit had that info in late August 2001 and nobody cared. CIA Director George Tenet was briefed on the Moussaoui threat on Aug. 23. The case received intense, high-level attention. Nobody cared.

Now it is clear that senior FBI officials Maltbie and Frasca did know about Moussaoui’s arrest. In fact, they knew the case so well that they denied Samit’s request for a warrant to search Moussaoui’s computer and belongings.

This decision to deny a warrant gave rise to the myth that “The Wall” between overseas intelligence and criminal investigations made the PATRIOT Act necessary. To this day this myth is cherished among right-wing radio talkers and has, just now, morphed into a clumsy justification for the White House’s sidestepping the FISA court and directing its own wiretap frenzy via the NSA. This is all pure fantasy.

Instead of clueless Carter-era restrictions on domestic spying or insufficient distrust of civil liberties, Samit cited “obstructionism, criminal negligence and careerism” by top FBI officials as what stopped his investigation.

• • •

While Samit was spending a solid three weeks trying to get Washington to act on his pre-9/11 terror fears, future 9/11 hijacker Hani Hanjour was raising suspicions with his flight training in Phoenix. Margaret Chevrette of the Pan Am International Flight Academy reported her worries to the FAA and somehow those concerns also made their way to CIA chief Tenet and into CIA memos of Aug. 2001, but the FBI never acted on them.

Yet on Sept. 12, FBI agents interviewed Chevrette for more information on Hanjour—reflecting the fact that another local FBI agent had notified FBI headquarters of the danger posed by Middle Eastern terrorists training at US flight schools.

Three different Bureau offices were hot on the terror plot in the days leading up to 9/11 and all were stiffed by Washington. If that is not institutional incompetence, heaven help the next 3,000 martyrs to J. Edgar Hoover’s suits.

No disaster, it seems, can force reform on the Bureau. The same people are still manning the posts at the FBI and Main Justice. They are going to miss the next terror attack because they are dead-certain to stop the last one. That’s what bureaucracies do: cover ass. The Bureau’s poisonous Andersen Consulting–with-arrest-powers culture remains unreformed and dangerously low-tech. New York City agents do not have enough e-mail addresses to go around, for example.

Instead of an effective anti-terror agency, the Bureau is morphing into a kind of Stasi Lite, keeping tabs on domestic subversives: assorted peaceniks, communists in Texas, and the League of Women Voters in Michigan, who had the gall to invite a critic of the PATRIOT Act to a panel discussion. There is a sort of logic to such surveillance: This what the FBI is good at, so this is what it does. Kinda of like looking for your car keys under a street light because the rest of the street is dark.

Still, for all the bungling in the dark the FBI has nothing to fear, not from a complicit Bush administration, not from a prostrate Congress, not from a bamboozled public. An e-mail sent to Agent Harry Samit on September 10, 2001 from a CIA Counterterrorism Center official identified only as “Cathy” points the way: “God help us all if the next terrorist attacks involves this same type of plane.”

JEFF A. TAYLOR is a contributor to Reason.com, where this article first appeared.