Vermont Sen. Bernie Sanders said Sunday that he would be willing to meet North Korea’s leader Kim Jong Un if elected president.

Sanders told CBS News that “meeting adversaries is not a bad thing to do” but added that President Trump has been “unprepared” for his discussions with Kim.

“I think, unfortunately, Trump went into that meeting unprepared,” Sanders said, likely referring to Trump’s meeting with Kim in June. “I think it was a photo opportunity and did not have the kind of the diplomatic work necessary to make it a success. But I do not have a problem with sitting down with adversaries all over the world.”

Other Democratic candidates would have a stricter approach to relations with North Korea. Former Vice President Joe Biden has said that he would not meet Kim “without any preconditions.”

"Look, we gave him everything he’s looking for. The president showed up, met with him, gave him legitimacy, weakened the sanctions we have against him," Biden said.

Pete Buttigieg has said that Trump’s meeting with Kim gave “legitimacy” to a rogue state.

Trump has met with Kim several times over the past two years to engage in nuclear negotiations, where North Korea would pursue a path of denuclearization in exchange for reduced sanctions. In addition to the meeting with Kim in June, Trump has met with North Korea’s leader in Vietnam in February 2019 and in Singapore in June 2018 for discussions.

No concrete deal on denuclearization has been achieved, despite Trump’s friendly personal relationship with Kim. Former National Security Adviser John Bolton has said that North Korea would never give up its nuclear arsenal.