Washington (CNN) When Secretary of Defense James Mattis told reporters that there was no "smoking gun" proving that Saudi Arabia's crown prince had orchestrated the murder of journalist Jamal Khashoggi, many remarked that the retired general, who has spent a career consuming intelligence assessments, should know better than to demand irrefutable proof.

The CIA has assessed with "high confidence," sources tell CNN, that an operation as elaborate and brazen as Khashoggi's murder in Istanbul could have been greenlit only by Crown Prince Mohammed bin Salman, known as MBS.

"When the intelligence community ascribes "high confidence" to a finding, to an assessment, to me, you can take that to the bank," former Director of National Intelligence James Clapper told CNN. "While there may not have been a video reflecting MBS directly giving direction to do away with Jamal Khashoggi, the evidence from many sources, I suspect, is so compelling that they came out with a 'high confidence' rendering."

The best analysis

That's the job, intelligence professionals insist: to offer the best analysis and most concrete conclusions possible to the policymakers, who then weigh it with their other priorities.

In terms of events in recent memory, the determination that Osama bin Laden was living on a compound in Abbottabad, Pakistan, was far from high confidence. The latest highest confidence he gave, Clapper said, was the assessment he and his colleagues had made that the Russians interfered in the 2016 presidential election.

"That's as close to a smoking gun or a slam dunk as you'll ever come, but you're never going use that terminology per se," he said.

The Khashoggi killing and Russian interference have offered the two most glaring examples of President Donald Trump acting at odds with the conclusions reached by the intelligence community. The President even took issue with the characterization of the assessment on the Washington Post journalist.

US Secretary of State Mike Pompeo (L) meets with Saudi Crown Prince Mohammed bin Salman in Riyadh, on October 16, 2018. - Pompeo held talks with Saudi King Salman seeking answers about the disappearance of journalist Jamal Khashoggi, amid US media reports the kingdom may be mulling an admission he died during a botched interrogation. (Photo by LEAH MILLIS / POOL / AFP) (Photo credit should read LEAH MILLIS/AFP/Getty Images)

"They did not come to a conclusion. They have feelings certain ways," Trump told reporters. "The CIA doesn't say (MBS) did it, they do point out certain things and in pointing out those things you can conclude that maybe he did or maybe he didn't."

When Secretary of State Mike Pompeo -- the first CIA director during the Trump administration -- went to Capitol Hill to brief senators alongside Mattis in the wake of Khashoggi's death, he echoed his boss's skepticism.

"There is no direct reporting connecting the Crown Prince to the order to murder Jamal Khashoggi," Pompeo told a gaggle of reporters following the briefing. The briefing was roundly criticized by senators of both parties for not including CIA director Gina Haspel, a decision they accused the White House of making.

Haspel is now set to brief a small bipartisan group of lawmakers Tuesday, including leaders of key Senate committees, according to a congressional source.

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Trump and Pompeo have argued that in the absence of concrete proof of the prince's role, the circumstantial evidence is outweighed by the United States' strategic national security, economic and oil interests with Saudi Arabia

But even if an apparent smoking gun were found, in any analysis it too would be questioned by analysts in the broader context of the situation.

"Even if you had an intercept of the Crown Prince saying, 'Yes, kill Khashoggi,' there would still be an analytical piece to that," said Steve Hall, the CIA's former head of Russia operations. "The idea that CIA or NSA or any of the intelligence organizations have to come up with DNA-style proof is something that both politicians and practitioners of intelligence know is sort of a false premise."

'A slam-dunk case'

In late 2002, then-CIA Director George Tenet told President George W. Bush that Iraqi President Saddam Hussein had weapons of mass destruction. "It's a slam-dunk case," he told Bush, according to a book by Bob Woodward. That phrasing, Woodward wrote, was "very important" in Bush's decision to go to war.

That, of course, turned out to be wrong and will forever be part of Tenet's legacy. Since then, Hall said, there's been less of an inclination inside the CIA to make determinations with such certainty.

"I think any president worth their salt understands the role of intelligence and the difference between a legal proceeding and an intelligence briefing," Hall added. "To say 'What I demand is absolutely a smoking gun before I'll take any action,' that's a policy decision, not an intelligence decision."