Former NBA star Dennis Rodman, and pal of North Korean leader Kim Jong Un, has been among those to get out front with congratulations to President Donald Trump on a meetup between the two countries.

“Well done, President Trump. You’re on the way to a historical meeting no U.S. president has ever done,” Rodman told the Associated Press, along with a say hey to the Kim clan family in Pyongyang.

But foreign policy experts were slightly more cautious in their assessment over what hurdles Trump may face in a meeting with the man he once called “Little Rocket Man”. The meeting was announced late Thursday. Some are worried the president may be “getting played” by a country that has proven itself fairly untrustworthy when it comes to nuclear weapons and promises.

Read:How the Trump-Kim meeting news moved markets

Here’s a roundup of the positive and negative reactions from some experts on Korean policy to that meetup that could come as soon as May:

• “North Korea has been seeking a summit with an American president for more than twenty years. It has literally been a top foreign policy goal of Pyongyang since Kim Jong Il invited Bill Clinton,” tweeted Jeffrey Lewis, director of the East Asia Nonproliferation Program at the Middlebury Institute of International Studies at Monterey.

“I wonder if Trump’s ‘aides’ have explained that to him. Or, if in their toddler-handling, they have led him to believe that this offer is something unusual. Or perhaps he imagines that only he can go [to] Pyongyang,” Lewis added.

• “Trump’s chaotic management style, erratic, moody personality, and chronic staffing problems, especially regarding East Asia. I just don’t see it, We can always hope, but it is just as reasonable to fear that Trump, the reality TV star who somehow stumbled into the presidency for which he is woefully unfit, will wander from decades of joint US-South Korea policy, about which he naturally knows nothing, and make some kind of deal for a ‘win’ that no other US official would endorse.” said Robert E. Kelly, professor of political science at Busan National University in South Korea, in a tweetstorm. (More here)

Kelly is also known as the “BBC dad” who unwittingly shot to fame last year after his two small children wandered in on a live TV interview.

Trump Accepts Invitation to Meet North Korea's Kim Jong Un

• “Engaging NK is very hard work. This is the beginning, not the grand solution. But it’s a very good start,” said Seoul-based Yonsei University Professor John Delury on Twitter. “I haven’t been in DC these past 6 months but this has the ring of truth. Trump is smart to meet KJU early & get to work. ‘Anything But Trump’ is not helpful. Oppose/ resist/ register to vote when he wrong/cruel/dangerous. This isn’t one of those times,” he added.

Read:Kim Jong Un vows to write a ‘new history of national reunification’ with South Korea

• “Talks with North Korea are a good idea; talks involving Trump are a very bad idea,” Van Jackson, a North Korea expert and former policy adviser in the U.S. office of the secretary of defense, told the Japan Times in an interview. “Trump likes taking gratuitous risks. There’s no theory of the case behind it; just a perverted version of ‘fortune favors the bold.’”

“Unfortunately the costs of his gamble if he’s wrong will cost lots of people’s lives and probably America’s position in Asia,” Jackson added.

• “There is good reason to talk with North Korea, but only if we are talking about something that is worth doing and that could be reasonably verified — otherwise we are setting ourselves up for a major diplomatic failure,” tweeted William Perry, former U.S. Secretary of Defense under President Bill Clinton.

• “This is one of those moments in history when you have to throw the Hail Mary, when you have to give it a shot,” Harry Kazianis, of the Center for the National Interest, told CNN.