Jose Padilla is known worldwide as the man who plotted with Al Qaeda to detonate a radiological "dirty bomb" in a major US city.

He allegedly presented his plan to top Al Qaeda leaders Abu Zubaydah and 9/11 mastermind Khalid Sheikh Mohammed. But according to US intelligence reports, both men doubted Mr. Padilla could pull off the attack.

For his part, Padilla told military interrogators that he never intended to carry it out. The former Taco Bell employee made the proposal in early 2002 as a way to justify fleeing Pakistan to avoid being sent to combat US forces in Afghanistan, says a government account.

So is Padilla – whose terror conspiracy case could go to a Miami jury Wednesday – a committed Al Qaeda operative, or merely a big-talking mujahideen wannabe who ultimately wanted to go home?

The answer to that question is important. Padilla isn't a run-of-the-mill enemy combatant apprehended on a foreign battlefield. He is a United States citizen, arrested on US soil, who was held in a military prison for 43 months and subjected to harsh interrogation techniques until he confessed.

Padilla was given due process to file a lawsuit challenging his treatment by the government. But as an enemy combatant, he was stripped of every other constitutional protection and right, including the right to know that a constitutional challenge had been filed on his behalf.

Many legal scholars and intelligence experts say Padilla's ordeal highlights the danger of a government that obtains information through secret, coercive means and then selectively releases some of it to justify its actions.

"This is the hallmark of an authoritarian state," says Larry Johnson, a former State Department counterterrorism official and former analyst at the Central Intelligence Agency.

"At many of the points at which the government said 'dirty bomb,' there was no opportunity to respond for the reason that Mr. Padilla was in solitary confinement and no lawyer had been able to talk to him about the charges," says Diane Amann, visiting law professor at the University of California, Berkeley.

The release of some details about Padilla and the dirty-bomb plot was justified by administration officials as supporting the public interest. But some information about Padilla and his interrogation must remain secret, officials say, to prevent revealing US intelligence sources and methods to Al Qaeda.

In the court of public opinion, Padilla stands convicted. His name is almost synonymous with dirty bomber. Yet, when it came time to put Padilla on trial, the government's case in Miami included no mention of a dirty bomb.

In his trial, Padilla is accused of providing material support to a terror group by attending an Al Qaeda training camp in Afghanistan. Federal prosecutors are using a broad conspiracy charge to allege that Padilla was a willing participant in a global terror campaign to wage violent jihad by murdering, kidnapping, and maiming people. Padilla denies it.

Although they seek a life sentence, prosecutors introduced no evidence of personal involvement by Padilla in planning or carrying out any specific terrorist plot or violent act.

There is a reason the government's case is so thin, legal analysts say.

If prosecutors brought the dirty-bomb plot or other alleged illegal actions by Padilla into the Miami case, it would open the door for courtroom scrutiny of the government's use of coercive interrogation techniques against Al Qaeda suspects, including Padilla. And that would have taken jurors deep into the shadowy underside of America's war on terror – a journey in Padilla's case that wends its way from his cell on an isolated wing of the US Naval Consolidated Brig in Charleston, S.C., through covert CIA interrogation sites overseas to an alleged torture chamber in Morocco.

This is a part of the war on terror the Bush administration would rather keep quiet. But details are emerging.

What they reveal is the aggressive – and at times, ruthless – pursuit of intelligence information, and the selective public release of some of that intelligence when it serves the administration's goals.

Plot hit airwaves in 2002

The Padilla story burst into the national consciousness in June 2002 when then-Attorney General John Ashcroft interrupted a trip to Moscow to make a dramatic televised announcement.

"We have disrupted an unfolding terrorist plot to attack the United States by exploding a radioactive 'dirty bomb,' " he said. Padilla was a "known terrorist" who had trained with Al Qaeda, studied how to wire explosives, and researched radiological dispersion devices, he told the world.

What he didn't say was that Padilla had been locked in a solitary confinement cell in New York City for the past month and that Padilla was only now being taken into military custody on the eve of a scheduled court hearing that would have required the government to legally justify Padilla's continued detention.

Instead, President Bush declared Padilla an "enemy combatant" who posed a "continuing, present, and grave danger" to US national security. The president said Padilla possessed intelligence information that could help prevent Al Qaeda attacks on the US.

Some officials offered a less dramatic take on the dirty-bomb plot than Mr. Ashcroft's. Then-Deputy Defense Secretary Paul Wolfowitz told the CBS "Early Show" that Padilla was "in the very early stages of his planning." He added, "I don't think there was actually a plot beyond some fairly loose talk."

Nonetheless, the dirty-bomb announcement sent shock waves across the country and immediately helped justify the use of coercive interrogation techniques against Padilla, analysts say. And it gave news reporters an irresistible tag line to link to Padilla's name – "dirty bomber."

The dirty-bomb stigma would later help the government battle constitutional challenges to Padilla's military detention, according to many legal scholars. And it helped rally public support for an array of tough counter-terror policies by feeding national anxiety about possible terrorist use of weapons of mass destruction.

Perhaps most important, these analysts say, the Padilla case presented US officials with a situation that resembled the often discussed "ticking time bomb" scenario. Under this hypothetical plot, a terrorist has been captured after planting a ticking time bomb in a busy public location. Officials face the moral dilemma of either using traditional noncoercive interrogation methods that can take hours, days, or weeks and risk the deaths of thousands of innocent people or resort to brutal tactics to quickly obtain information to discover and defuse the bomb. Under the scenario, saving thousands of lives is viewed as the greater good that justifies using torture against the terrorist.

Mr. Bush has repeatedly stated that his administration does not use torture. But he has also acknowledged that in certain instances harsh interrogation methods have been authorized and used to help protect the nation.

Although civil libertarians protested Padilla's detention without charge, there was no significant public outcry.

Terror war innovation: long detention

The dirty-bomb allegation emerged from information obtained through a Bush administration innovation in the war on terror. That innovation called for the open-ended detention of terror suspects to facilitate aggressive, prolonged interrogations. The questioning was often accompanied by specially authorized harsh interrogation techniques, including isolation, sensory deprivation, and stress positions, among others, according to former interrogators.

No judge in an American courtroom could permit the introduction of information gathered under such coercive techniques, in part because they carry a high risk of producing unreliable results. If the technique is coercive enough, a subject will say whatever it takes to make it stop, former interrogators say. In addition, the rules of procedure and long-established constitutional protections forbid the use of coerced statements as evidence in a trial.

But the rules of the courtroom are not necessarily the rules of the interrogation room. Senior Bush administration officials made clear that once an individual is classified as an enemy combatant, he is no longer entitled to the protections of the Geneva Conventions and the US Constitution.

Because Padilla was held in solitary confinement under secret conditions, no one was aware of what was happening to him. The initial constitutional debate revolved around whether Padilla had a right to consult a lawyer or whether the government could hold him in isolation indefinitely.

In February 2004, then White House Counsel Alberto Gonzales told a meeting of the American Bar Association that citizens who take up arms against America don't deserve legal counsel. Any individual rights, he said, "must give way to the national security needs of this country to gather intelligence from captured enemy combatants."

Mr. Gonzales added, "The stream of intelligence would quickly dry up if the enemy combatants were allowed contact with outsiders during the course of an ongoing debriefing. The result would be the failure to uncover information that could prevent attacks," he said. "This is an intolerable cost, and we do not believe it is one required by the Constitution."

Two months later, lawyers were arguing Padilla's case before the US Supreme Court. Justice Ruth Bader Ginsburg wanted to know if there was any check on the powers being claimed by the executive branch to collect intelligence through coercive interrogations. "Suppose the executive says, 'Mild torture, we think, will help get this information'?" she asked. "Some systems do that to get information."

"Well, our executive doesn't," said then-Deputy Solicitor General Paul Clement.

A few minutes later, Justice Antonin Scalia, an anchor on the court's conservative wing, said he found nothing in his research to support Bush's assertion of unchecked authority to wage the war on terror. "It doesn't say you can do whatever it takes to win the war," he said.

His comment raised a huge red flag for the administration. That evening, coincidentally, the CBS program "Sixty Minutes II" broadcast the first images of detainee abuses at Abu Ghraib in Iraq.

A month later, at the height of the Abu Ghraib scandal and with Padilla's case pending at the Supreme Court, the Justice Department held a highly unusual press conference. Officials announced that after two years of interrogation, Padilla had confessed to involvement in the dirty-bomb plot and other activities with Al Qaeda.

"We now know much of what Jose Padilla knows. And what we have learned confirms that the president of the United States made the right call," said James Comey, then deputy attorney general at the Justice Department.

Padilla's Supreme Court case was dismissed by a 5-to-4 vote on a technicality. The justices said Padilla's lawyers should have filed their suit in South Carolina rather than New York. Scalia provided the key fifth vote in a decision that effectively allowed the administration to continue to hold and question Padilla in the brig.

Padilla's lawyers filed a new suit in South Carolina and, by 2005, were again at the steps of the Supreme Court. But rather than allow an airing of the issue at a high court that many analysts believe to be sympathetic to Padilla, the administration transferred him from military custody into the criminal-justice system.

With jury deliberations about to begin in Miami, legal scholars expect more major twists and turns in the Padilla saga. Among moves to watch:

•If Padilla is acquitted, will the government try to return him to the brig?

•If Padilla's lawyers file a civil suit to try to get his military detention case before the Supreme Court again, will the government argue that such a suit must be immediately dismissed to avoid revealing state secrets?

When Federal Bureau of Investigation agents first took Padilla into custody, administration officials thought they had nabbed an intelligence prize. Five years later, legal and intelligence analysts say, these claims look increasingly hollow as the administration maneuvers to keep Padilla from having a meaningful day in court. Its tactics are also keeping the public from knowing the truth about Padilla and the dirty-bomb plot, they say.

"You don't go on the Internet and spend a day reading and become an expert on how to put together a dirty bomb," says Mr. Johnson, the counterterrorism expert. "I'm not knocking folks who work at Taco Bell, but that's not a place you'd go to ramp up your skills" as a nuclear jihadist.

• Parts 1 and 2 appeared Monday and Tuesday.