Donald Trump could have good strategic reasons to cancel a meeting with Kim Jong-un.

The US President says it's because Kim has been angry and hostile.

But Tufts University Korean studies professor Sung Yoon Lee told Larry Williams Trump is trying to improve his position.

"The real reason is not necessarily the name calling but the blatant realisation that he's walking right into a trap."

However, he is confident the summit will almost certainly go ahead, saying it is not a matter of if, but when.

"There are political victories for both sides and Kim Jong-un has to go back to playing both sides."

LISTEN ABOVE AS SUNG YOON LEE SPEAKS WITH LARRY WILLIAMS