A top Trump administration official has all but admitted that the US stance toward North Korea talks is now a hardline one.

What this means, some analysts say, is that the American position will sink any chance for progress in US-North Korea negotiations over ending its nuclear program.

In a briefing with reporters on Thursday, a senior State Department official made a stunning remark when asked if the Trump administration agrees on how to handle the complexities of talks with North Korea.

“Nobody in the administration advocates a step-by-step approach,” the official said. “In all cases, the expectation is a complete denuclearization of North Korea as a condition for all the other steps ... being taken.” In other words, for Pyongyang to receive any kind of benefits like sanctions relief, it has to dismantle its entire nuclear arsenal first.

That contrasts greatly with the administration’s past stance and immediately led experts to pan the comment — and the Trump administration’s negotiation strategy.

“Insisting on disarmament as a condition for peace will lead to exactly the opposite of disarmament and peace,” tweeted MIT nuclear expert Vipin Narang.

“Only through practical reciprocal steps will we get closer to denuclearization & peace and away from dangerous & irresponsible ‘fire & fury’ threats,” Arms Control Association Director Daryl Kimball also tweeted.

Here’s why analysts closely following the US-North Korea drama are so worried: Pyongyang for years has said that the only way it would consider giving up its nuclear weapons is through a step-by-step process where both sides offer reciprocal, commensurate concessions. By resolving smaller disagreements, like lifting sanctions in exchange for the closure of an important nuclear facility, over time the US and North Korea would eventually arrive at the grand prize: the end of Pyongyang’s nuclear threat.

Twice it seemed that the Trump administration understood this. In Singapore last June, President Donald Trump and North Korean leader Kim Jong Un agreed to a four-step process. The first two steps were about improving US-North Korea ties, and only after this would the third part — discussing denuclearization — come into play.

And this January, just one month before Trump and Kim would meet for a second time in Vietnam, America’s envoy for North Korea talks Stephen Biegun gave a speech at Stanford where he effectively said the administration would adhere to a step-by-step approach.

“From our side, we are prepared to discuss many actions that could help build trust between our two countries and advance further progress in parallel on the Singapore summit objectives of transforming relations, establishing a permanent peace regime on the peninsula, and complete denuclearization,” he said.

(It’s worth noting that the anonymous diplomat from the briefing is very likely Biegun, since the transcript includes a question where a reporter asks about the official’s previous comments at Stanford.)

In short, this abrupt change in tone isn’t trivial. The North Koreans pay very close attention to any and all statements coming from the US government, and what they just heard is that the US wants “all or nothing.” It’s therefore possible that Pyongyang will get angry at the new rhetoric, thereby threatening the future of negotiations and possibly putting both nations back on the path to war.

“That could very well backfire,” says Harry Kazianis, a North Korea expert at the Center for the National Interest, by enticing Pyongyang “to push back with an intercontinental ballistic missile test in the coming weeks.”

“If that happens,” he continued, “here comes ‘fire and fury 2.0.’”

Why the official would make such a jarring statement

Experts tell me there are three main reasons the American diplomat chose to signal a complete change in course.

First, Trump scuttled the Hanoi summit last month by asking Kim to give up his entire nuclear arsenal in exchange for near-complete sanctions relief. By most all accounts, Kim bristled at the request, and both leaders walked away from the talks before a planned lunch and signing ceremony.

But if that’s what Trump wants, the rest of his administration must follow. Perhaps the official was simply noting the president’s new position on North Korea.

Second, the US may just be trying to look tough after an underwhelming summit. “This was a political statement to gain leverage and not the actual approach the administration is going to take,” David Kim, a former State Department official working on North Korea, told me, but added that “the tone certainly worries me.”

Perhaps by indicating that the US will play hardball from here on out, the US aims to have North Korea moderate its own hardline position. That ploy, experts say, is unlikely to work since Pyongyang is quite adamant that it would only abide by a step-by-step process.

And finally, the official (who, per the transcript, is likely Biegun) might be trying to fend off hardliners in the Trump administration. As the Washington Post reported last month, National Security Adviser John Bolton and Secretary of State Mike Pompeo have both expressed skepticism at Biegun’s approach toward North Korea. Not only do they think Kim won’t give up his nuclear weapons, as the US intelligence community assesses, but they seem to think that Biegun may give up too much in the process.

By stating that the US won’t abide by the step-by-step approach, then, the diplomat perhaps aims to quell internal criticism.

What’s clear, though, is that this statement won’t be taken kindly by the Kim regime. The US may want to continue negotiations, but comments like the official’s yesterday threaten to end them.