Appearing on Fox Business Network’s Your World on Monday, former U.S. Ambassador to the United Nations John Bolton told guest host Trish Regan that there is only one diplomatic solution left with regard to North Korea:

I think there's one diplomatic approach left, and that's to China, to convince China it's in their interest, their national interest, to see the Korean peninsula [reunite] essentially under South Korean control; to eliminate the nuclear program in the North, and thereby eliminate the risk that Japan will go nuclear in response to it.

This is a hard argument to make, but as I say, we've been playing the diplomatic game for a long time, and all that it's done is give North Korea time to advance its program.

Concerning recent sanctions, Regan asked Bolton:

If they don't do what we need them to do, are these sanctions really going to be enough? And I say this because the impact is roughly a billion dollars to them. They have an economy that's worth an estimated $28 billion. So, will this really affect things, or are we still talking about margins here?

Bolton responded:

Well, number one, you have to assume that to get to the billion dollar figure that everybody enforces the sanctions. That would be a heroic assumption, untrue with respect to every other sanctions resolution we've adopted. ...

Finally, let's be clear, China is very worried about a catastrophic collapse of the North Korean regime. A billion dollars to China is chump change. They could give it to North Korea, say: "Send us your coal for free. We'll buy that bucket of pebbles over there for a billion dollars."

Bolton added that “this has been the pattern for a quarter of a century. The U.S. itself relaxed sanctions, I'm sorry to say, during the Bush administration, and has had to reimpose them subsequently. And North Korea has been very successful at evading sanctions. China, Russia, others have helped — Iran certainly is going to help.”

“[The alternatives are] very limited,” Bolton noted grimly. “I think they're very limited after 25 years of failed efforts. Our diplomatic options are quite limited, and that's why there is, unfortunately, talk about a military option to protect the United States against the day when North Korea in fact can reach the entire continental United States with nuclear weapons."

When Regan questioned Bolton on whether the U.S. would ever allow the geopolitical situation to reach that point, he replied:

Well, I'm with you. I wouldn't do it. But I'm telling you, I will predict right now, we will hear people in this country, including in the government, say right up to the day when the missile lifts off, "Why don't we just sit down and talk with the North Korea?" We have talked to them for 25 years. It hasn't worked; it won't work now.

Regan asked, almost incredulously: “So, alternatively, we go in and we — we're actually exercising our military might there?” To which Bolton responded: “Well, that's the last resort.”