North Korean leader Kim Jong Un has “the upper hand” over U.S. President Donald Trump after threatening to cancel an all-important nuclear weapons summit that Trump has already claimed as a political victory, a former U.S. ambassador tells CTV News in an exclusive interview.

CTV’s Washington Bureau Correspondent Richard Madan spoke with Bill Richardson, who has a deep understanding of North Korean politics as a former U.S. negotiator with the rogue nation. Richardson has also served as Governor of New Mexico and as the U.S. ambassador to the United Nations.

At the moment, it’s unclear if the summit, scheduled for June 12 in Singapore, will actually happen. North Korea threatened this week to pull out of the meeting after South Korea and the U.S. carried out joint military drills.

Richardson believes the summit will likely go through.

“I’d say 65-35 that it does happen. Because both sides need it, and it’s good for the world,” said Richardson, speaking in Washington, D.C. “Both sides are jockeying, maneuvering. They’ve got leaders that are similar in temperament. But I say it happens.”

North Korea’s threat shows that they want leverage ahead of the talks, Richardson said, and the move has given them an early advantage.

“Right now, I think North Korea has the upper hand because they’ve threatened to cancel the summit. And the summit is very important for President Trump and the North Koreans,” he said.

Even so, North Korean leader Kim Jong Un needs the summit more than Trump, Richardson said, because he has more at stake.

“He wants an assurance that he can stay in power, he doesn’t want anyone to knock him off. He wants sanctions lifted. He wants to be on par with the United States as a major power in Asia, ego-wise. He wants to rebuild his country economically and he knows the only way to do it is with the West and the United States and the removal of sanctions.”

North Korea’s last-minute posturing before the meeting is typical of their unpredictable style of diplomacy, Richardson said. Ahead of the meetings, North Korea released three Americans who’d been held for years. Richardson said North Korea likely expects the U.S. to make similar concessions.

“So it’s a little tactics, leverage, bluster. It’s a combination too of the North Koreans flexing their muscles. You know, they’ve got 40 nuclear weapons, so they’ve got some muscles.”

Richardson, a Democrat who served as an ambassador under Bill Clinton, was critical of Trump’s approach on the North Korea file, describing his tactics “macho.”

He also accused the Trump administration of having too many cooks in the kitchen, when Secretary of State Mike Pompeo -- who has met Kim twice -- should really be quarterbacking the talks.

“It’s not helpful. When he says that he’s going to walk out … it’s like a spoiled kid,” Richardson said.

Regardless, Richardson said Trump can take credit for pushing the two nations toward negotiations, and he encouraged the president not to back down amid the mixed messaging.

“Go through with it. It’s worth the risk. You deserve credit, Mr. President, for agreeing to the summit. For sending Pompeo to meet with Kim Jong Un, for talking to the South Koreans, Japan. This is good for the region, for the world. Just stop talking about Nobel Prizes and that you deserve all the credit,” he said.

“That’s my bit of advice -- which he’s not going to follow, because he won’t change.”

The seasoned negotiator also offered advice to Canada as NAFTA talks in Washington, D.C., hit a critical juncture. Some U.S. officials have marked Thursday as a hard deadline to ink a new deal.

“I think you’ve got to find ways, the prime minister and the Canadian government, to maybe calm down my president a bit,” he said with a laugh.

“It’s going to be a disaster if that dissolves. It’s mainly our administration that wants to screw it up. So Canada, be a mediator between Mexico. That’s my advice to Canada.”

With a report from CTV’s Washington Bureau Correspondent Richard Madan