By Shaun Boyd

DENVER (CBS4) – Colorado U.S. Senator Cory Gardner is Congress’ point-man on North Korea and has been advising President Donald Trump in preparation for the summit.

(credit: CBS)

(credit: CBS)

“Just had a call with the National Security Council from Singapore about what’s happening,” Gardner said in an interview just a few hours before the historic meeting.

Cory Gardner (credit: CBS)

As chair of the East Asia Subcommittee, Gardner has lead the U.S. strategic response on North Korea, laying the groundwork for the summit.

US President Donald Trump (R) poses with North Korea’s leader Kim Jong Un (L) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. – Donald Trump and Kim Jong Un have become on June 12 the first sitting US and North Korean leaders to meet, shake hands and negotiate to end a decades-old nuclear stand-off. (Photo credit: SAUL LOEB/AFP/Getty Images)

“For a big, uncertain moment… There’s no guarantee about what’s going to be said in the next several hours. Whether he means denuclearization, we’re about to find out,” Gardner said.

(Photo credit: SAUL LOEB/AFP/Getty Images)

He says Kim Jong Un’s definition of denuclearization may be different than ours.

(credit: CBS)

“To me denuclearization means the whole kit and kaboodle. We take North Korea and we eliminate their weapons of mass destruction program, whether that’s chemical or nuclear or other types of weaponry.”

Gardner says North Korea has much to gain from the meeting.

(credit: CBS)

“Look at their economy, it’s in shambles. They could be welcome to the community of nations. They could have a thriving economy. Their people could be provided food, humanitarian relief. They could see oil relief. They could see any number of things coming their way if they’re responsible.”

But he says the regime has a history of backing out of deals with the United States. The pre-summit one-on-one, he says, will be telling.

Sen. Cory Gardner (credit: CBS)

“At this point, it’s necessary to find out what Kim Jong Un actually expects and what he wants. I think we have to be eyes open. I’ve encouraged the president and his staff multiple times, if at any point he gets the sense that denuclearization is not on table, he needs to walk away,” Gardner said. “The United States has no higher diplomatic offering than the President of the United States, and if it’s not going to be about denuclearization, we shouldn’t give Kim Jong Un the air time, so to speak, that he desires.”

Gardner says he expects the dictator will agree to a deal. But he says – except for maybe some humanitarian aid for North Koreans who are starving – the U.S. will continue to apply maximum pressure on the regime until there is concrete verifiable progress toward denuclearization.

(Photo credit: SAUL LOEB/AFP/Getty Images)

Watch the two leaders meet for the first time in Sentosa Island, Singapore:

Shaun Boyd is CBS4’s political specialist. She’s a veteran reporter with more than 25 years of experience. Follow her on Twitter @cbs4shaun.