North Korean leader Kim Jong Un meets with U.S. Secretary of State Mike Pompeo on May 9.Reuters / KCNA

A senior White House official said on Thursday that while it “wasn’t helpful” for the North Koreans to call the vice president of the United States a “political dummy” and threaten America with nuclear war, it wasn’t rhetoric alone that doomed Donald Trump’s planned nuclear summit with Kim Jong Un in Singapore.

Instead, speaking to reporters in a background briefing, the official aired a range of grievances about the Trump administration’s dealings with North Korea in the lead-up to the June 12 meeting—only some of which had been previously disclosed. They amounted to evidence of “a profound lack of good faith.”

The summit could have been canceled for any number of other reasons—one being that the U.S. might ultimately have surmised from conversations with the North Koreans that a summit would have been a waste of time. But the briefing offered at least the first sustained case from the administration about why it pulled out.

North Korea, the official noted, had left “a trail of broken promises” since March 8, when Trump announced his intention to meet with Kim. That announcement came after a South Korean delegation to Washington informed the president that the North Korean leader was committed to denuclearization and willing to halt his nuclear and missile tests while U.S.-South Korea military exercises proceeded. First North Korea backtracked on the military exercises by furiously objecting last week to a routine joint air-force drill, the official noted. Then, after agreeing during U.S. Secretary of State Mike Pompeo’s latest visit to Pyongyang to send representatives to Singapore to work out logistics for the summit, the North Koreans stood up their U.S. counterparts without explanation. The American advance team “waited and they waited. The North Koreans never showed up,” the official said.

The official added that some of the preparatory work for the summit had ground to a halt in recent days “because we simply couldn’t get [the North Koreans] to pick up the phone” and end their “radio silence”—with three weeks to go until an unprecedented encounter between the leaders of the United States and North Korea. “In fact the first communication that we’ve received in a week arrived last night in the form of” North Korea’s statement attacking Mike Pence and warning of a “nuclear-to-nuclear showdown,” the official said.

The official also cast doubt on North Korea’s much-hyped destruction of its mountainous nuclear-test site on Thursday, claiming that the North had reneged on a pledge to Pompeo and the South Korean government to permit international nuclear experts to witness and verify the demolition. North Korea allowed in only journalists instead. As a result, the official explained, “We will not have forensic evidence that much was accomplished. It’s possible that the tunnels were detonated in a way that will still allow them to be used in the future.”

The official’s overriding tone was one of exasperation, which didn’t bode well for Trump’s suggestions on Thursday that the summit just might still happen as scheduled or at a later date. The official noted that a North Korean statement last week explicitly rejected the very “complete, verifiable, and irreversible” denuclearization that U.S. policymakers are committed to achieving with North Korea. Citing North Korea’s pledges in a joint declaration with South Korea in late April, the official asked, with an incredulous laugh, “How could [North Korea] declare that it is moving forward with the goal of complete denuclearization but object to denuclearization in a statement two weeks later? It’s a head-scratcher.”

Asked how the Trump administration could continue trusting the North Koreans after the dysfunctional preparations of the past week, the official didn’t exactly sound upbeat. “They don’t make it easy.”