North Korean leader Kim Jong-un's call for global denuclearization could be part of a ploy to entice either the fading administration of President Barack Obama or his successor into negotiations over its nuclear weapons program, a former U.S. ambassador said Wednesday.

John Bolton, who served as top U.S. envoy to the U.N. in 2005-2006, made the point in an article contributed to the Boston Herald, calling for caution in dealing with a regime that has a track record of violating a series of agreements over its nuclear programs.

The North's leader made the call for a denuclearized world during a key meeting of the Workers' Party while at the same time pledging never to use its nuclear weapons first unless its sovereignty is infringed upon and vowing to fulfill its non-proliferation obligations as a "responsible nuclear state."

South Korea denounced the remarks as an expression of his intention to hold on to the nuclear programs.

"But in much of the foreign press coverage of his remarks, Kim got what he wanted: The media detected a new tone amidst all the familiar rhetoric. For those Westerners obsessed with finding conciliatory gestures by nuclear-aspirant authoritarian regimes like Iran and North Korea, the new tone is never hard to find," Bolton said.

Bolton, currently a senior fellow at the American Enterprise Institute, also said the North may be trying to "reprise circumstances at the end of the Clinton administration," referring to late 2000, when relations between Washington and Pyongyang warmed so significantly that then-President Bill Clinton even considered visiting the North.

A Clinton trip did not materialize, but a top North Korean military official paid a visit to Clinton at the White House in October 2000 and then-U.S. Secretary of State Madeleine Albright traveled to Pyongyang later that month and met with then-North Korean leader Kim Jong-il, father of the current leader.

"Although Kim's father had to be satisfied with a visit by Secretary of State Madeleine Albright, Obama would be an easier get. Kim could figure that even a farewell visit by peripatetic Secretary of State John Kerry would at least return the North to the status quo in 2000, after long years of isolation from Washington's top leadership," Bolton said.

The North could also be targeting Obama's successor, he said.

"Kim may be calculating that Hillary Clinton would like a significant foreign-policy accomplishment early in her presidency, thereby demonstrating her seriousness and, early on, setting herself ahead of Obama's international pace," Bolton said. "While Donald Trump authored 'The Art of the Deal,' Kim knows that Pyongyang has outmatched Washington in every negotiation since the Korean War. He may think the challenge is worth the risk."

 Bolton also called for greater attention on the North Korea issue.

"Since the North has fully mastered the art of saying (and promising) one thing while doing precisely the opposite, how to handle the rogue regime should be a significant topic in our upcoming presidential debates," he said. (Yonhap)