In the months leading up to the killing of Osama bin Laden, veteran intelligence analyst Robert Cardillo was given the nickname “Debbie Downer.” With each new tidbit of information that tracked bin Laden to a high-walled compound in northern Pakistan — phone records, satellite imaging, clues from other suspects — Cardillo cast doubt that the terror network leader and mastermind was actually there.

As the world now knows well, President Barack Obama ultimately decided to launch a May 2011 raid on the Abbottabad compound that killed bin Laden. But the level of widespread skepticism that Cardillo shared with other top-level officials — which nearly scuttled the raid — reflected a sea change within the U.S. spy community, one that embraces debate to avoid “slam-dunk” intelligence in tough national security decisions.

The same sort of high-stakes dissent was on public display recently as intelligence officials grappled with conflicting opinions about threats in North Korea and Syria. And it is a vital part of ongoing discussions over whether to send deadly drone strikes against terror suspects abroad — including U.S. citizens.

The three cases provide a rare look inside the secretive 16 intelligence agencies as they try to piece together security threats from bits of vague information from around the world. But they also raise concerns about whether officials who make decisions based on their assessments can get clear guidance from a divided intelligence community.

At the helm of what he calls a healthy discord is Director of National Intelligence James Clapper, who has spent more than two-thirds of his 72 years collecting, analyzing and reviewing spy data from war zones and rogue nations. Clapper, the nation’s fourth top intelligence chief, says disputes are uncommon but absolutely necessary to get as much input as possible in far-flung places where it’s hard for the U.S. to extract — or fully understand — ground-level realities.

“What’s bad about dissension? Is it a good thing to have uniformity of view where everyone agrees all the time? I don’t think so,” Clapper told The Associated Press in an interview Friday. “…People lust for uniform clairvoyance. We’re not going to do that.”

“We are never dealing with a perfect set of facts,” Clapper said. “You know the old saw about the difference between mysteries and secrets? Of course, we’re held equally responsible for divining both. And so those imponderables like that just have to be factored.”

Looking in from the outside, the dissension can seem awkward, if not uneasy — especially when the risks are so high.

At a congressional hearing last month, Rep. Doug Lamborn, R-Colo., read from a Defense Intelligence Agency report suggesting North Korea is able to arm long-range missiles with nuclear warheads. The April 11 disclosure, which had been mistakenly declassified, came at the height of Kim Jong Un’s sabre-rattling rhetoric and raised fears that U.S. territory or Asian nations could be targeted for an attack.

Within hours, Clapper announced that the DIA report did not reflect the opinions of the rest of the intelligence community, and that North Korea was not yet fully capable of launching a nuclear-armed missile.

Two weeks later, the White House announced that U.S. intelligence concluded that Syrian President Bashar Assad has probably used deadly chemical weapons at least twice in his country’s fierce civil war. But White House officials said the intelligence wasn’t strong enough to justify sending significant U.S. military support to Syrian rebels who are fighting Assad’s regime.

Because the U.S. has few sources to provide first-hand information in Syria, the intelligence agencies split on how confident they were that Assad had deployed chemical weapons. The best they could do was conclude that the Syrian regime, at least, probably had undertaken such an effort. This put Obama in the awkward political position of having said the use of chemical weapons would cross a “red line” and have “enormous consequences,” but not moving on the news of chemical weapons use, when the occasion arose, because the intelligence was murky.

Lamborn said he welcomes an internal intelligence community debate but is concerned that the North Korean threat was cavalierly brushed aside.

“If they want to argue among themselves, that’s fine,” said Lamborn, a member of the House Armed Services Committee. However, he also said, “We should be cautious when evaluating different opinions, and certainly give credence to the more sobering possibilities. … When it comes to national security, I don’t think we want to have rose-colored glasses on, and sweep threats under the rug.”

Clapper said that, in fact, U.S. intelligence officials today are more accustomed to predicting gloom and doom. “We rain on parades a lot,” he said.

Current and former U.S. intelligence officials say the vigorous internal debate was spawn from a single mistake about a threat — and an overly aggressive response.

Congress demanded widespread intelligence reform after the Sept. 11, 2001, terror attacks, to fix a system where agencies hoarded threat information instead of routinely sharing it. Turf wars between the CIA and the FBI, in particular, were common. The CIA generally was considered the nation’s top intelligence agency, and its director was the president’s principal intelligence adviser.

The system was still in place in 2002, when the White House was weighing whether to invade Iraq. Intelligence officials widely — and wrongly — believed that then-dictator Saddam Hussein possessed weapons of mass destruction. By December 2002, the White House had decided to invade and was trying to outline its reasoning for doing so when then-CIA Director George Tenet described it as “a slam-dunk case.”

The consequences were disastrous. There were no WMDs, but the U.S. wound up in a nearly nine-year war that killed nearly 5,000 American soldiers, left more than 117,000 Iraqis dead, and cost taxpayers at least $767 billion. The war also damaged U.S. credibility throughout the Mideast and, to a lesser extent, the world. Tenet later described his “slam-dunk” comment as “the two dumbest words I ever said.”

Two years later, Congress signed sweeping reforms requiring intelligence officials to make clear when the spy agencies don’t agree. Retired Amb. John Negroponte, who became the first U.S. national intelligence director in 2005, said if it hadn’t been for the faulty WMD assessment “we wouldn’t have had intelligence reform.”

“It was then, and only then that the real fire was lit under the movement for reform,” Negroponte said in a recent interview. “In some respects it was understandable, because Saddam had had all these things before, but we just allowed ourselves to fall into this erroneous judgment.”

To prevent that from happening again, senior intelligence officials now encourage each of the spy agencies to debate information, and if they don’t agree, to object to their peers’ conclusions. Intelligence assessments spell out the view of the majority of the agencies, and highlight any opposing opinions in a process similar to a Supreme Court ruling with a majority and minority opinion.

The result, officials say, is an intelligence community that makes assessments by majority vote instead of group-think, and where each agency is supposed to have an equal voice. In effect, officials say, the CIA has had to lean back over the last decade as officials have given greater credence to formerly marginalized agencies. Among them is the State Department’s Bureau of Intelligence and Research, which warned before the 2003 Iraq invasion that the CIA had overestimated Saddam’s prospects to develop nuclear weapons.

Also included is the DIA, which has increased its ability during the Iraq and Afghanistan wars to gather ground-level intelligence throughout much of the Mideast and southwest Asia. In an interview, DIA director Army Lt. Gen. Michael Flynn would not discuss his agency’s debated assessment on North Korea, but described a typical intelligence community discussion about “ballistic missiles in name-that-country” during which officials weigh in on how confident they feel about the information they’re seeing.

“In the intelligence community we should encourage, what I would call, good competition,” Flynn said. He added: “The DIA, in general, is always going to be a little bit more aggressive. …As a defense community, we’re closer to the war-fighting commanders; it may be in that part of our DNA.”

Without the all the varying strands of information pieced together from across the intelligence agencies, officials now say the bin Laden raid would not have happened.

The CIA was running the manhunt, but the National Security Agency was contributing phone numbers and details from conversations it had intercepted in overseas wiretaps. The National Geospatial Agency provided satellite imagery of the Abbottabad compound — from years past and more recently — to get a sense of who might be living there. And it produced photos for a tall man walking the ground inside the compound — even though they were never able to get a close look at his face.

One of the compound’s balconies was blocked off by a seven-foot wall, Cardillo said, raising questions about who might want his view obscured by such a tall barrier. Officials also were keeping tabs on the people who lived in the compound, and trying to track how often they went outside.

Cardillo was vocal about his skepticism in each strand of new information he analyzed during the eight months he worked on the case, prompting colleagues to rib him about being a “Debbie Downer.”

“I wasn’t trying to be negative for the sake of being negative,” Cardillo, a deputy national intelligence director who regularly briefs Obama, said in an interview Friday. “I felt, ‘Boy, we’ve got to press hard against each piece of evidence.’ Because, let’s face it, we wanted bin Laden to be there. And you can get into group-think pretty quick.”

To prevent that from happening, officials encouraged wide debate. At one point, they brought in a new four-man team of analysts who had not been briefed on the case to independently determine whether the intelligence gathered was strong enough to indicate bin Laden was there.

Their assessment was even more skeptical than Cardillo’s. In the end the call to launch the raid was so close that, as officials have since said, it might as well have come down to a flip of a coin.

In most intelligence cases, the decisions aren’t nearly as dramatic. But the stakes are always high.

Over the last four years, the Obama administration has expanded the deadly U.S. drone program in its hunt for extremists in terror havens. The drones have killed thousands of people since 2003 — both suspected terrorists and civilian bystanders — among them four U.S. citizens in Pakistan and Yemen.

The Justice Department this week said only one of the four Americans, Anwar al-Awlaki, who officials believe had ties to at least three attacks planned or carried out on U.S. soil, was targeted in the strikes. The other three were collateral damage in strikes aimed at others.

Though policy officials make the final call on when to strike, the intelligence community builds the case. Analysts must follow specific criteria in drone assessments, including near certainty of the target’s whereabouts and the notion that bystanders will not be killed. They must also look at the likelihood of whether the terror suspects can be captured instead of killed.

In these sorts of life-and-death cases, robust debate is especially necessary, Clapper said. And if widespread doubts persist, the strike will be canceled.

“It is a high bar, by the way, and it should be,” Clapper said. “If there is doubt and argument and debate — and there always will be as we look at the totality the information we have on a potential target — we damn well better have those debates and resolve those kinds of issues among ourselves the best we can.”

Few have been more skeptical of the decision-making behind the drone strikes than Sen. Ron Wyden, an Oregon Democrat who has sat on the Senate Intelligence Committee since 2001. Earlier this year, he threatened to block Senate confirmation of CIA Director John Brennan until the White House gave Congress classified documents outlining its legal justification for targeting American citizens in drone strikes. The documents were turned over within hours of Brennan’s confirmation hearing.

Generally, Wyden says, spy assessments have become far more reliable over the last decade, and especially since the flawed Iraq intelligence. But he maintains Congress should be given greater access to classified documents to independently verify intelligence analysis and assessments — and safeguard against being misled.

“Certainly, solid analysis from the intelligence community is one of the most important sources of information that I have,” Wyden said in an interview this month. “And if you look back, and the analysis is incorrect or if it’s written in a way that portrays guesses at certainties, that can contribute to flawed decision-making.

“That’s why I felt so strongly about insisting on actually getting those documents with respect to drones,” Wyden said. “I’ve got to be able to verify it.”

Clapper, who has been working on intelligence issues for a half-century, is well aware of how jittery many Americans feel about the spy community. The internal debates, he believes, should bolster their confidence that intelligence officials have thoroughly weighed all aspects of some of the world’s most difficult security issues before deciding how high a threat they pose.

“I think it’d be very unhealthy — and I get a lot of pushback from people — if I tried to insist that you will have one uniform view and this is what I think, and that’s what goes. That just wouldn’t work,” he said. “There is the fundamental tenet of truth to power, presenting inconvenient truths at inconvenient times. That’s part of our system.”

(AP)