(CNN) International condemnation is pouring in after North Korea's sixth nuclear test. But what makes this more than just another step forward for Pyongyang is this: the claim that a miniaturized hydrogen bomb can now be placed on an intercontinental ballistic missile.
After two separate intercontinental ballistic missile tests in July, North Korea claims it has the ability to reach the US mainland. That puts enormous pressure on Washington to come up with the right response.
In my conversations with key US officials who are properly plugged into North Korea, the picture is grim, but there also remains some room for maneuver to defuse any potentially catastrophic outcomes.
The Kim regime is "not suicidal," says former US Defense Secretary William Perry. He has engaged with the regime since he was part of the Clinton administration that achieved the 1994 Agreed Framework negotiation with the country's founder Kim Il Sung.
Perry said North Korea has "three goals ... (the) most primary goal is to preserve the Kim dynasty, to preserve the regime ... the second goal is to gain international recognition and the third goal is to improve their economy."
"We have little or no prospects, I think, of achieving the goal of getting them to get off the nuclear weapons. Short of going to a war, which would become a nuclear war, and we do not want that."
Perry added: "the negotiation in the last number of years have all failed, I believe because they've been based on a faulty premise. They've been based on the premise that North Korea was willing to give up its nuclear weapons. We have to understand what the goals of North Korea are if we're going to have successful negotiation."
China has a vital role to play, but to date it appears the Chinese government has concluded that a nuclear North Korea is less of a threat than a collapsed North Korea.
Analysts and experts say this is for humanitarian, economic and strategic reasons.
Not only does Beijing fear an influx of millions of North Koreans across its border, but crucially, it fears losing North Korea as a buffer zone between it and US military forces on the Korean Peninsula. It fears the US and its allies becoming the dominant military force right on China's northern border. And that's another reason the US has to assure China that it is not seeking regime change in North Korea, says Secretary Perry.
"China has to understand that our goals include being willing to sustain the regime in North Korea," Perry said.
"So unless, we adopted a negotiating strategy which has these three objectives ... allowing North Korea's regime to stay in place. Secondly, to give them international recognition and third ... giving them economic improvement, then we will not have much success."
Perry says China would agree to a set of negotiating goals that included those three objectives, but he cautions, "we have to be realistic about what our real options are. Not what we would like to have happen. We have to accept North Korea as it is, and not as we would wish it to be."
In June, former CIA analyst Sue Mi Terry was part of a rare delegation to meet with North Korean officials who were trying to figure out ways to restart negotiations. She came away from the meeting in Sweden with a dose of realpolitik, a wake-up call so to speak.
"Well, it's a very pessimistic picture," she told me. "The North Koreans have told us that denuclearization is completely off the table. Nuclear weapons are no longer negotiable."
"They are so close to perfecting their nuclear arsenal, to completing their program and capability to reach the mainland United States with an ICBM, with a nuclear tipped ICBM. They said why would we give this up? This is our last final deterrent, (our) only means of survival."
"So nuclear weapons, discussing nuclear weapons is off the table. They're only willing to meet to possibly talk about a peace treaty to formally end the Korean War, but not over the nukes," she said.
Importantly, Terry says the generals in US President Donald Trump's cabinet, National Security Advisor H.R. McMaster and Defense Secretary James Mattis, understand that the military option is not doable.
She painted this picture: "There's over 10,000 artillery pieces, within 60 seconds of Seoul. We have 20 million people living in Seoul. We have 20,000 American expats. We have some 20,500 American soldiers living in Seoul, and they understand (that a military option is not feasible), never mind that North Korea is already a nuclear power."
Negotiations will be difficult too as the North Koreans want a formal peace treaty with the US to finally end the Korean War.
Terry says that's not possible, either.
"...it's impossible to get to a peace treaty option because what the North Koreans really want by formally concluding a peace treaty is really to be able to get ... US forces out of the Korean peninsula."