Former CIA chief unsure Trump 'has done the homework needed' on North Korea

“Kim Jong Un knows his program inside and out,” former CIA Director Hayden said.

Hayden said he hopes any summit between Trump and North Korean leader Kim Jong Un "stays at the level of principles," rather than delving into specifics.

Hayden said that, ideally, in the summit, “They talk about denuclearization, allow each side to kind of cower within the ambiguity of denuclearization, and then, seriously begin a process that makes the peninsula less dangerous than it is today.”

The former intelligence official also discussed his concern that demanding that North Korea entirely give up its nuclear program could end "in a very bad place."

"I totally agree with Sen. Rubio," Hayden said. "These folks are not going to get rid of all their nuclear weapons. And if President Trump's 'brand,' and that's the right word here, going into this meeting demands something like that, this is going to end up in a very bad place."

Raddatz asked whether Trump and Kim might characterize the outcome an eventual summit differently with, for example, Trump's saying he accomplished "denuclearization" of the Korean Peninsula, and Kim's referring simply to "arms control."

Hayden said that would be a positive result.

"I hope that's where we come out," he said. "I think that's the most optimistic scenario. You have the meeting. Everyone smiles. Everyone shakes hands. And everyone agrees on a work program that they give to their staffs that moves the Korean Peninsula in a direction of being more stable, more transparent, less prone to war. But I don't think we're going to have a parade of missiles or weapons going through some destruction site that we can put on camera."

“I think [President Trump] is simply trying to delegitimize the Mueller investigation, the FBI, the Department of Justice, and he’s willing to throw almost anything against the wall" to see if it sticks, Hayden said.