A looming face-to-face summit between President Donald Trump and North Korean ruler Kim Jong Un should be canceled, according to a political scientist who said the U.S. leader isn't prepared for such high-stakes negotiations.

The meeting is simply too risky because Trump apparently has a limited knowledge of North Korea's complex politics, Robert Kelly, associate professor at Pusan National University, told CNBC.

Trump "doesn't know a great deal about Korea — we know that he doesn't read very much, he watches a lot of television and his national security staff is sort of in chaos right now," he said, referring to the recent appointment of National Security Adviser John Bolton.

In contrast, "the North Koreans have been working on this stuff for a long time, so they're going to come in there and know every single detail and they're going to be ready to negotiate down deep into the weeds," Kelly stated.

"The first thing Kim Jong Un is going to do in the room is give a 40-minute speech about U.S. war crimes going back to the Korean War," Kelly continued, posing the question of whether the president is "ready to sit there and listen" as Kim talks.