Secretary of State Mike Pompeo touted his visit to North Korea this weekend as a victory, highlighting Kim Jong Un's supposed concession of inviting inspectors to a defunct nuclear testing site.

This was met with the equivalent of an eye roll from many experts.

"This is almost them reselling the same car to the Americans," said Andrea Berger, a senior research associate at the Middlebury Institute of International Studies. "We're not inspecting a new action or a new facility. They already dismantled the site."

The testing site, Punggye-ri, was closed six months ago because it was no longer needed by North Korea. Some of the tunnels in the mountain complex may have collapsed, rendering them unusable.

North Korea invited inspectors to witness to site's demolition in April, only to retract that and allow only journalists to attend. Extending the same offer to the Americans six months later, Berger said, amounts to an old concession dressed up as a new breakthrough.

That's not how the U.S. sees the offer. After his fourth trip to Pyongyang, Pompeo said Monday that he had made "significant progress" in the effort to force North Korea to abandon its nuclear weapons program.

"Chairman Kim invited inspectors to visit the Punggye-ri nuclear test site to confirm that it has been irreversibly dismantled," State Department spokeswoman Heather Nauert said in a statement.

A satellite photo of the Punggye-Ri nuclear test site in May. HANDOUT / Reuters

Despite a historic summit between President Donald Trump and Kim in Singapore in June, relations between the two countries have been rocky since then. Trump canceled a visit by Pompeo in August, citing a lack of progress in the talks, and negotiations have slowed.

Korea-watchers say the main difficulty is that the U.S. and North Korea have different opinions of what "denuclearization" actually means, and what each is prepared to give up to get there.

Some experts predict the North has no plans to give up its weapons, or at least not without unlikely security guarantees from the U.S. and its allies.

According to this theory, Kim and his officials are instead trying to buy time so they can make progress on other fronts, such as building economic ties and even declaring a long-awaited peace with South Korea, as well as increasing their international standing.

Inviting inspectors to an old testing site is an example of this calculus, according to Vipin Narang, an associate professor of political science at MIT.

"Kim has mastered the art of milking a single cosmetic concession for months to burn clock," he wrote on Twitter.

The real takeaway from this Punggye-ri pledge is that Kim has mastered the art of milking a single cosmetic concession for months to burn clock. We are still talking about Punggye-ri and Sohae 6 months after he pledged to dismantle them. Brilliantly selling the same horse twice. pic.twitter.com/sAKq7ZABdV — Vipin Narang (@NarangVipin) October 7, 2018

James Acton, co-director of the Nuclear Policy Program at the Carnegie Foundation for International Peace, called the invitation to Punggye-ri "a joke" and "pure PR."

No information was given about which inspectors might be allowed to visit the site, nor how much access they would be given. One way this concession may be beneficial, however, is if the North Koreans were to expand their invitation to other sites, according to Berger.

"If that step can be translated into a conversation about inspectors potentially being let in to other facilities, that would be interesting," she said.

Pompeo also discussed a second summit between Trump and Kim, without providing further information. Although the enthusiasm around the first event appeared to soon fizzle out, that's not to say there aren't wins to be had if the U.S. manages its expectations, Berger said.

"If you're setting your sights on complete nuclear disarmament by North Korea, you can wait a very long time," she said. "But there are feasible and desirable things short of full nuclear disarmament," such as restricting its nuclear arsenal and increasing the transparency of its weapons program.