Any meeting between President Donald Trump and North Korean leader Kim Jong Un "probably was a bad idea in the first place," Thomas Hubbard, former U.S. ambassador to South Korea, told CNBC on Thursday.
It was "probably doomed from the outset," added Hubbard, a principal negotiator of the 1994 framework that had been aimed at ending North Korea's nuclear weapons program.
Meanwhile, former U.S. Ambassador Nicholas Burns, in an earlier CNBC interview, said Trump made the "right move" on Thursday in canceling the Kim summit.
Referring to angry statements in recent days out of North Korea, Burns said these were not the actions of leader who sincerely wants to work toward dismantling his nuclear apparatus.
North Korean Vice Minister of Foreign Affairs Choe Son Hui said early Thursday, "I cannot suppress my surprise at such ignorant and stupid remarks gushing out from the mouth of the U.S. vice-president."
The remarks out of Pyongyang were in response to what Vice President Mike Pence said in a Monday interview on Fox News. Pence said, "As the president made clear, this will only end like the Libyan model ended if Kim Jong Un doesn't make a deal."
The reference to Libya, which was forced to give up its nuclear weapons in 2003 and later saw the regime of its former leader Moammar Gadhafi decimated by NATO during the country's civil war, set North Korea on edge.
Trump's decision to pull the plug on the Kim meeting demonstrates U.S. strength, which is a "good thing right now," said Burns, currently a professor at the Harvard Kennedy School of Government.
A summit may happen at some point, but for now, keeping U.S. sanctions in place against North Korea is the "leverage" to possibly bring Kim around, said Burns, whose 27-year career in foreign service spanned both Republican and Democratic administrations.
Burns served as U.S. ambassador to NATO and was the State Department's third-ranking diplomat during the presidency of Bush 43. He also advised George H.W. Bush and Clinton.