In intellectual life, “I don’t understand” can be the scariest and most powerful words one can utter.

When one is surrounded by smart people, it is embarrassing to profess ignorance. Saying you don’t know something can be seen as a sign of weakness in a milieu where knowledge is the most important tool. When confronted with the limits of their understanding, some people will try to bluff their way through. As I noted in “The Ideas Industry,” sheer confidence can be a potent tool in debate. This is particularly true for professors terrified of displaying the limits of their knowledge to students. They may try to bluff their way through a gap in knowledge. From this fear, profs start doing things like insisting that Australia is only a continent and not a country.

The best profs and the sharpest minds are also the most unafraid to profess what puzzles them. When certain colleagues say, “I’m confused” in a seminar, that is a bad omen for the presenter. If they profess confusion, it is not because they are stupid. It is because they are very smart and the speaker has said something that does not make sense. It could be a logical contradiction, a hidden assumption or an unspoken shibboleth. The point is, in the academy, the smartest people in the room are also the ones most likely to profess ignorance.

Is this true in politics as well?

Ignorance comes up an awful lot in conversations about president Trump. Consider the story by my Washington Post colleagues Carol Leonnig, Shane Harris and Greg Jaffe about whether President Trump reads the Presidential Daily Brief (PDB). The official pushback was that Trump’s ignorance was actually an advantage, because it allows him to ask the tough questions:

“‘The president asks hard questions,’ [CIA Director Mike Pompeo] said in public remarks last month. ‘He’s deeply engaged. We’ll have a rambunctious back-and-forth, all aimed at making sure we’re delivering him the truth as best we understand it.’

“Trump’s admirers say he has a unique ability to cut through conventional foreign policy wisdom and ask questions that others have long taken for granted. ‘Why are we even in Somalia?’ or ‘Why can’t I just pull out of Afghanistan?’ he will ask, according to officials.

“The president asks ‘edge’ questions, said one senior administration official, meaning that he pushes his staff to question long-held assumptions about U.S. interests in the world.”

Clearly, Trump is unafraid to ask the basic existential questions on foreign policy. Is that a trait that leads to better policymaking? There is a strong case for newcomers to the executive branch to ask tough and basic questions, like “Why can’t I just pull out of Afghanistan?” Changes in administration are precisely the moment when foreign policy assumptions must be challenged to see if they are living truth or dead dogma.

The thing is, for the provocative question to work, the questioner needs to have enough information to interrogate the answers that are proffered. As Elizabeth Saunders argued last month in Foreign Affairs, “Experienced leaders provide better oversight of foreign policy decision-making because they are more likely to ask hard questions, spot poor planning, or recognize unrealistic proposals.”

The guy who does not read the PDB most definitely does not possess the information or expertise to challenge shibboleths. Trump might be right to question the wisdom of protracted engagement in Afghanistan, but his inventory of ignorant foreign policy beliefs is so massive that it is easy to dismiss him even if he is onto something. This is a man who believed it was possible to “take the oil” in Iraq and that NATO functioned like a dues-paying society with other countries in arrears. He believed Xi Jinping’s history of Sino-Korean relations because he doesn’t know any better. He did not comprehend the foreign policy ramifications of his Jerusalem decision. Trump does not know what he does not know.

Trump’s factual and historical ignorance means that even when he asks the good question, a skilled operator can deflect the challenge. Consider the debate over Afghanistan strategy last summer. As Greg Jaffe and Missy Ryan reported in the Post, Defense Secretary Jim Mattis had a ready answer to Trump’s tough question:

“Last summer, Trump was weighing plans to send more soldiers to Afghanistan and was contemplating the military’s request for more-aggressive measures to target Islamic State affiliates in North Africa. In a meeting with his top national security aides, the president grew frustrated.

“‘You guys want me to send troops everywhere,’ Trump said, according to officials in the Situation Room meeting. ‘What’s the justification?’

“‘Sir, we’re doing it to prevent a bomb from going off in Times Square,’ Mattis replied. …

“It was Mattis who made the argument that would, for the moment at least, sway Trump to embrace the status quo — which has held for the past two presidents.

“‘Unfortunately, sir, you have no choice,’ Mattis told Trump, according to officials. ‘You will be a wartime president.’”

If we’re being honest, Mattis did not give a great answer. But it was good enough to deflect Trump. As I noted last year, “[Trump] lacks the gravitas and expertise to countermand his military advisers, even when his instincts push him in that direction. Trump also lacks any civilian staffers with the knowledge and wherewithal to put an unconventional solution onto the table.”

This problem has only gotten worse since the summer. As the Rob Porter saga has made abundantly clear, Trump has no reservoir of loyal experts to bring into the administration. The White House’s response has been to bring in no experts. This empowers the remaining officials even more. And as Emma Ashford noted in The National Interest:

“[Trump has not] been able to recruit those who criticize the liberal international consensus — his views on trade and immigration, and his repugnant statements and personal views, have alienated even those who might be willing or happy to attempt to reshape U.S. foreign policy in any other administration. Instead, Trump has been forced to rely on a mixture of unqualified individuals and former military officers. Many other offices remain unfilled.”

Trump’s problem is not that he always asks the wrong questions. In some instances, he is not. The problem is that he lacks the information to properly assess the answers he gets.

Trump is not the smart professor playing dumb. He is the lazy student trying to bluff his way through the presidency as a very stable genius. And everyone, including his own Cabinet, knows that he is bluffing.

Daniel W. Drezner is a professor of international politics at the Fletcher School of Law and Diplomacy at Tufts University and a regular contributor to PostEverything.