President Donald Trump’s Thursday announcement that he had agreed to meet with North Korean leader Kim Jong Un came as a shock to many. It could also be an incredibly risky gamble.

One reason is that the US president has agreed to give the North Koreans something they’ve wanted for years — direct negotiations with an American leader over their nuclear program — with relatively little time for advance preparation. (The meeting will happen by May, per a South Korean official.)

Granted, talking is much better than the past few months of escalating war threats on both sides, according to most experts. And the North did seem to agree to a temporary freeze on nuclear and missile tests. But the decision to meet also raises a very different set of risks, one intimately tied to the nature of President Trump himself: He is very easy to manipulate.

To understand the problem here, consider a meeting Trump had about North Korea last year with Chinese President Xi Jinping. Trump came to his first meeting with the Chinese leader last April convinced that China could easily force Pyongyang to give up its nukes. Xi then gave Trump a quick recap of the complex history of Chinese-Korean relations — which promptly changed the president’s mind.

“After listening for 10 minutes, I realized it’s not so easy,” the president recalled in an interview with the Wall Street Journal. “I felt pretty strongly that they had a tremendous power [over] North Korea. ... But it’s not what you would think.”

There is no way the North Koreans don’t know about this incident, and no way they failed to learn the obvious lesson. The Kim regime knows the president has a set of clear weaknesses — he’s easily swayed by flattery, not terribly interested in policy details, and deeply invested in his reputation as a dealmaker. Put those together and it’s easy to imagine the North Koreans tricking Trump into a deal that, in the long term, helps their strategic position while hurting America’s.

“This could be the start of something good,” says Alexandra Bell, senior policy director at the Center for Arms Control and Non-Proliferation. “It could also fail miserably, hurting the chances of a diplomatic solution to this long-simmering crisis.”

The North Korea meeting isn’t ordinary, and Trump isn’t an ordinary president

Every country Trump has visited during his presidency has figured out some way to flatter him.

French President Emmanuel Macron brought Trump to a Bastille Day military parade in Paris, which he liked so much that he’s now demanding one in Washington. The Polish government bused in Trump fans for his speech so he could have the adoring audience he’s used to. Japanese Prime Minister Shinzo Abe gave Trump a $4,000 gold-plated golf club and posed for pictures in MAGA-style hats with the slogan “Donald and Shinzo: Make Alliance Even Greater.”

Authoritarian countries have been even better at this game. Saudi Arabia projected Trump’s face onto the side of a hotel and gave him a red-carpet rollout. China’s President Xi literally shut down Beijing’s picturesque Forbidden City to give Donald and Melania Trump a private tour.

Foreign countries of all stripes have given Trump over-the-top receptions for one simple reason: It works. The trip to France apparently helped repair Trump-Macron relations after Macron attacked Trump during his 2017 presidential campaign. Trump’s warm personal relations with Xi have softened his anti-China campaign stance; Trump hasn’t followed through on his many, many promises to punish the country for what he sees as unfair trade practices.

There is no doubt in anyone’s mind that North Koreans will have picked up on what every other country knows before one of the country’s highest-stakes political summits since the end of the Korean War. Even if the meeting isn’t in Pyongyang, there will be plenty of ways Kim can stroke the president’s ego during their in-person session — giving him lavish gifts, for example, or praising various Trump Organization products (such as Trump Wines or Trump University).

This isn’t the only psychological lever Kim can pull. The president’s deep belief in his own prowess as a dealmaker will make him inclined to come away from the negotiations with some kind of deal. The fact that he doesn’t seem particularly interested in learning the finer points of policy makes it easier for the North Koreans to convince him that a terrible agreement actually isn’t so bad — and after much flattery, he might very well be convinced to make a “great deal.”

Throughout his presidency, Trump has displayed little interest in learning about foreign affairs — plus his diplomatic corps is dangerously understaffed. There is no US ambassador to South Korea; the top US diplomat working on North Korea issues, Joseph Yun, announced his retirement last month. And Trump appeared to do very little consultation with the rest of the government before his decision to sit down with Kim.

“A summit with [Kim Jong Un] without serious preparation or any sense of what the agenda is gives up most of our leverage before we even get to the table,” says Laura Rosenberg, the former National Security Council director for China and Korea. “The fact that State [was] apparently in the dark on this is also a serious cause for concern.”

In short: Trump, a man whom other countries have frequently and successfully manipulated, appears set to have personal talks with the leader of an extremely dangerous country on an issue where the stakes are literally nuclear.

What could possibly go wrong?

It’s worth not being too tough on Trump here. According to some analysts, this could, of course, be a step in the right direction.

Meeting in person is certainly less dangerous than issuing threats to unleash “fire and fury” on North Korea or lobbing insults at “Little Rocket Man” Kim Jong Un. And it’s not guaranteed that Kim will be able to successfully manipulate Trump; he isn’t exactly a seasoned negotiator himself.

“It’s extremely positive, of course, that the emphasis is now on dialogue as opposed to threats and counter-threats,” says Kingston Reif, director for disarmament and threat reduction policy at the Arms Control Association. “That Kim Jong Un has apparently agreed to a testing freeze ... would have been very hard to imagine only a week ago.”

The problem, though, is that the positive movement could only be temporary. If talks are bungled, the outcome could be dire indeed.

The first and most obvious scenario is that the North Koreans could dupe Trump into accepting a bad deal. They could offer some kind of vague concession — like some toning-down of the anti-US rhetoric — in exchange for Trump making major concessions on, say, recognition of the North’s status as a nuclear power or withdrawing US troops from South Korea. This could strengthen the Kim regime domestically and makes US allies less secure without much in the way in the way of benefits for the US.

Second, Trump himself could screw things up.

A direct Kim-Trump meeting is not an end in itself. To tangibly decrease the threat from North Korea’s nuclear program, the US and North Korea would have to engage in complex and lengthy discussions. But when you have an unprepared negotiator — or one with unreasonable expectations, like Trump’s oft-expressed desire that the North give up all of its nukes without any major concessions on the US’s part — it’s easy to shut down the diplomatic process.

“We’re at the very beginning of the road to a diplomatic resolution,” Reif notes. “A summit is a bold move but requires careful preparation to ensure that this is the start and not the end of a diplomatic process.”

Third, and perhaps most dangerous, is that the North’s attempts to manipulate Trump could backfire. If they anger or personally offend him, all bets are off. Another one of Trump’s quirks is that he’s quick to anger and holds grudges deeply — after one reporter described him as a “short fingered vulgarian,” he would periodically send the reporter photos with his hands circled in gold Sharpie for years afterward.

This aspect of Trump’s personality demonstrably shapes policy; the president’s recent decision to impose tariffs on steel and aluminum imports was, per NBC, a reaction to Trump having a bad week politically and wanting to lash out. If North Korea insults him, it’s not difficult to imagine him ordering some kind of retaliation — potentially setting off another dangerous escalation cycle.

“Consistent and disciplined messaging will be extremely important. Going through with this summit will attract enormous criticism, especially if expectations aren’t managed well,” says Jenny Town, assistant director of the US-Korea Institute at Johns Hopkins University. “Let’s see if Trump is up to these challenges.”