Read: Japan and Russia muscle their way into the Trump-Kim dialogue

“OMG. A reminder of who Kim J[o]ng UN really is. Eyes wide open, Mr. President,” the Obama-era ambassador Michael McFaul stated on Twitter in reaction to the reports. “Kim Jong Un is a homicidal tyrant who deliberately starves his people and murders those who di[s]please him,” wrote Democratic Senator Chris Murphy. “It’s simply heartbreaking to know … that his biggest global cheerleader is the President of the United States of America.”

The explanation for Trump’s bizarre fawning over Kim, however, isn’t necessarily as simple as the president not understanding who Kim really is, or alternately understanding who Kim really is and cheering on his reign of terror.

Trump once offered a utilitarian rationale for why he heaps flattery on North Korea’s dictator, who operates gulags and assassinated his own half brother: “Let it be whatever it is to get the job done,” he said last fall, after a first meeting between both leaders ended a year of military brinkmanship over Kim’s development of long-range nuclear weapons that could reach the United States. “I have a good chemistry with him. Look at the horrible threats that were made. No more threats.”

Read: America’s alliance system will face one of its biggest tests yet

That ceased being true after the breakdown of nuclear talks between the two leaders in Vietnam earlier this year. Kim has resumed his threats, and his government has directed its wrath at advisers such as Secretary of State Mike Pompeo and National Security Adviser John Bolton, who have resisted relieving sanctions on North Korea until it commits to giving up its weapons of mass destruction. So far, though, Kim has stopped short of reviving nuclear and long-range missile tests that would likely set off Trump, in a sign that he’s still interested in making a deal with the American president, if not Trump’s more hard-line subordinates.

When I asked William Ury, a co-author of the business-negotiation bible Getting to Yes, about Trump’s perplexing praise for Kim, he told me that he saw a clear method to the president’s seeming madness—one that he felt was deliberate because Trump has exhibited a pattern of behavior, even amid overwhelming criticism.

Trump appears to be operating with the philosophy “The cheapest concession you can make in a negotiation is to give the other fellow a little respect,” which buys you a counterpart willing to hear you out and maybe even work with you, said Ury, who is also a co-founder of Harvard Law School’s Program on Negotiation. “I’ve found that to be true over 40 years of being in this field, whether you’re talking family, business, or high-stakes nuclear showdowns.”

Read: Trump’s bet on Kim might not pay off

The president also seems to be adhering to a principle recommended in Ury’s book: being “soft on the people” you’re negotiating with (in this case, Kim) while being “hard on the problem” (in this case, maintaining unprecedented international sanctions on North Korea and walking away from the Vietnam talks when Kim wouldn’t agree to completely denuclearize).