North Korean leader Kim Jong Un. AP Photo/Wong Maye-E Kim Jong Un is a "smart cookie," President Donald Trump said recently of North Korea’s leader.

"He’s 27 years old," Trump mused. "His father dies, [he] took over a regime. So say what you want but that is not easy."

Kim, who has assassinated his internal rivals using anti-aircraft guns and chemical weapons, seeks to develop a nuclear missile that can reach the United States. These actions may provoke a "major, major conflict" with the US, Trump has said: "I hope he’s rational."

In my research on political leaders, I’ve found that different people have different definitions of rationality. The core question – "What is my best move?" – is often answered by a leader’s idiosyncratic beliefs, rather than by an immediately obvious logic of the situation as seen by external observers.

The history of dealing with inscrutable foreign leaders is instructive: From Hitler to Saddam to Khrushchev, understanding the other is the most urgent challenge of national security decision-making for the US

To influence Kim’s behavior, we must ask: What is his particular vantage point?

South Korean soldiers wear North Korea's military uniforms and hold North Korea's flags, acting as North Korean soldiers, as they take part in a re-enactment the battle of the Korean war during a commemorative war victory event to mark the 66th anniversary of the the Korean war on September 22, 2016 in Waegwan, South Korea. Chung Sung-Jun/Getty Images

Lessons of the past

In the spring of 1943, the director of the first centralized US intelligence agency, Colonel William "Wild Bill" Donovan, sought help in understanding Hitler. Donovan wanted to give President Franklin D. Roosevelt a sense of "the things that make him tick."

Donovan called Walter C. Langer, a psychoanalyst helping with the war effort, in for a meeting: "What do you make of Hitler? If Hitler is running the show, what kind of a person is he? What are his ambitions?"

Langer combined the scant intelligence on Hitler with insights from Freudian psychoanalysis into a study on Hitler. He accurately predicted that Hitler would commit suicide rather than be captured by Allied forces. But his insight was largely irrelevant to the military strategy for defeating Germany. The report took so long to produce that the war was nearly over by the time it was delivered to Donovan.

More recently, the former top UN weapons inspector Charles Duelfer and I studied what made former Iraqi president Saddam Hussein tick. For several years, Duelfer was the senior point of contact between Iraq and the US After the regime fell, he produced the definitive report on its weapons programs.

Looking for logic in Saddam’s decisions, we found instead a morass of idiosyncratic thinking. Most astonishing was his misreading of President George W. Bush’s June 2002 speech to the West Point Military Academy. Intending to warn Saddam that he must comply with UN demands or face war, Bush struck a stern tone. The "gravest danger to freedom," he said, was "unbalanced dictators with weapons of mass destruction." Later in the speech, Bush praised President Ronald Reagan for standing up to "the brutality of tyrants."

What Bush said and what Saddam heard were two very different things.

via Wikimedia

Saddam did not see himself as unbalanced, and he knew that he did not have weapons of mass destruction. And US-Iraq relations had been excellent under President Reagan, Saddam recalled. The United States had tilted toward his side during the Iran-Iraq war. Things started to deteriorate only under the Bushes, in his view.

Our analysis showed that Saddam believed Bush could not have been talking about him. Instead, Saddam concluded he must have been threatening North Korea, not Iraq. Kim Jong Il, father of Kim Jong Un, possessed the nuclear weapons that the Iraqi president desired but did not have.

Bush was dumbfounded by the lack of Saddam’s response to his threats. Later he asked, "How much clearer could I have been?"

Duelfer and I had the academic luxury of malleable deadlines in studying Saddam. Langer spent many months on his Hitler study. Scholarship on Kim Jong Un may be too slow for the current crisis. Major decision-makers may instead need to rely on their intuition.

Former Secretary of Defense Robert S. McNamara with former President John F. Kennedy. wikicommons / JFK Library, Cecil Stoughton

Empathize with your enemy

Former Secretary of Defense Robert S. McNamara spoke about intuition in a 2003 documentary about his role in the Kennedy and Johnson administrations. McNamara revealed crucial new details about the 1962 Cuban missile crisis. Soviet leader Nikita Khrushchev had smuggled nuclear missiles into Cuba, threatening 90 million Americans. President John F. Kennedy’s first reaction was that he must destroy them with a massive air strike. This would have courted war with the USSR.