The lobby of CIA headquarters in Langley. (Larry Downing/Reuters)

Michael V. Hayden, a principal at the Chertoff Group and visiting professor at George Mason University’s Schar School of Policy and Government, was director of the National Security Agency from 1999 to 2005 and the Central Intelligence Agency from 2006 to 2009.

I don’t envy the president-elect’s intelligence briefers. Candidate Donald Trump stormed through the election as a primal force of dystopia, anger and accusation. More often than not, there was little effort to back up accusations with fact. Many of them were, in fact, not true.

During a rally in Buffalo on Tuesday, Donald Trump said he helped clean up rubble at Ground Zero on 9/11. (Reuters)

Hence, we were told we could “take out” terrorists’ families because the 9/11 hijackers’ families were aware of the attack and fled North America just before the hijackings. And that the president of the United States actually “founded ISIS”; he didn’t make errors in policy and set the conditions for the Islamic State terrorist group to emerge, he founded it. And Mexicans (rapists, mostly) are still streaming across our southern border. Most Muslims “hate us.” (Check out that 9/11 celebratory video from New Jersey.)

Then the candidate disregarded intelligence that Russia was hacking the emails of the Democratic National Committee, claiming, “I don’t think anybody knows it was Russia that broke into the DNC” and “Our country has no idea.”

With that record, a fair question is: What role will facts and fact-bearers play in the Trump administration? What happens when he is told that Syrian refugees are already extremely vetted? Or when his intel briefer dishes up that the Russians really aren’t targeting the Islamic State?

What controls — new data or preexisting mythology? For many authoritarian populists (think the leaders of Turkey, Venezuela and Russia), it’s the latter.

The intelligence community sometimes makes mistakes, but it strives to create a fact-based, inductive view of the world. From as much data as it can acquire, it works to create general conclusions. Not surprisingly, there are often tensions with policymakers who tend to be deductive, trying to apply their vision to specific situations.

And there are special issues when data-based conclusions collide with vision-based expectations. We had long and serious discussions in 2007 when a draft estimate assessed that Iran had stopped work on an aspect of its nuclear weapons program. I suspect a similar dynamic unfolded in the Obama administration when evidence pointed to the rebirth of al-Qaeda in Iraq in the face of claims that the organization was “on the run.” The unpleasant fact is always contentious.

I’ve had my debates with presidents and vice presidents over intelligence estimates. I’ve argued over facts and analysis. But all this was done under the broad mantle of empiricism, the belief that truth emanated from evidence and experience, not from a priori reasoning, intuition or faith — even faith in self.

The president-elect has powerful instincts that seem to have served him well during the campaign. But instinct only goes so far. The president-elect does not know more about the Islamic State than the generals.

So now, as the weight of the office should become apparent, how much will the president-elect accept that he needs intensive briefings and readings to supplement a thin personal database on global affairs?

What kind of attention span will he have for issues that are complex, nuanced, historical and seemingly endless: “So that’s it for the Islamic State, Mr. President-elect. What next? Jabhat al-Nusra? Boko Haram? AQAP? Or should we cover Sunnism vs. Shiism?”

How much humility will be on offer — as in the president-elect admitting a lack of knowledge in order to better learn? How much will he listen to absorb, rather than to rebut? The comment this summer about reading the briefers’ body language to divine their opposition to administration policy was not encouraging.

Most important, which of the president-elect’s existing instincts and judgments are open to revision as more data is revealed?

One important sign will be who attends briefings with him. In August, candidate and staff questioned the integrity and competence of the intelligence community even before their first session.

Better now if the candidate enlists folks to help him leverage the output of a 100,000-person, $53 billion annual enterprise largely designed to serve him and make him wiser.

For its part, the intelligence community needs to understand how the president-elect learns and how contrarian ideas are best served up to him. Not an easy task.

And the intelligence community needs to stand its ground, even, or especially, when it is irritating the client in chief. Simply writing down an unwelcome assessment or saying it once is not enough.

Many factors legitimately influence decision-making, including a president’s intuition. Intelligence is rarely the sole determinant of an action. Yet good intelligence should create the basis, and set the outside boundaries, for rational choices.

That’s the tough task before the president-elect’s intelligence briefers, and they owe its accomplishment to their professional ethic, to the nation — and to the new president.