We know much of this because Trump laid it out in his news conference before heading home. He said Kim had offered to dismantle the Yongbyon nuclear facility but only in exchange for total sanctions relief.
"They were willing to de-nuke a large portion of the areas that we wanted, but we couldn't give up all of the sanctions for that," Trump said. ". . . We had to walk away from that."
Trump is correct; that would be a terrible deal. Yongbyon represents a small and antiquated portion of Kim's nuclear infrastructure. But Trump can't claim that he was surprised by that bad offer. CNN reported that Trump's top officials told him for days this was Kim's position and Kim would not budge.
Special envoy Stephen Biegun had been negotiating with his North Korean counterparts for weeks, but he couldn't get the North Koreans to do more, like hand over a declaration of what they have. The notion that Trump, charismatic deal-maker that he is, could bridge that gap in a couple of meetings was never plausible.
Contradicting Trump, North Korea's foreign minister said Kim had asked for only partial sanctions relief for shutting down Yongbyon. But even that would have been a bad deal, at least according to Moon Chung-in, a top adviser to South Korean President Moon Jae-in.
Speaking in Washington this week, he said, "It's a good deal for North Korea and a bad deal for the United States."
No one is pushing harder for a U.S.-North Korea deal than the South Korean government. If it knew the United States could not accept the deal Kim was putting forward, of course Kim knew that as well. He's evil but not stupid.
Most likely, Kim's offer was a poison pill, meant to signal just enough flexibility to get Trump to Hanoi but to ensure that the negotiations would fail. Trump walked directly into the trap and doesn't even seem to realize it.
On top of all that, Trump committed two huge, unforced errors. He refused to say the negotiation's goal was to fully de-nuclearise North Korea. "I don't want to put myself in that position, from the standpoint of negotiation," he said. That contradicts everything his officials keep saying and actually weakens his own negotiating position.
Trump also let Kim off the hook for the treatment of Otto Warmbier, the American hostage who died days after being returned from imprisonment in North Korea. By accepting Kim's claim he wasn't aware of Warmbier's treatment, Trump once again believed a dictator over his own officials while undermining any future attempts by Warmbier's family to hold Kim responsible for their son's death.
Secretary of State Mike Pompeo claimed repeatedly that progress was made in Hanoi but gave zero information on what he was talking about. Inside the administration, there's already work on a Plan B in the (increasingly likely) event that Pompeo's effort finally fails.
There's another choice besides this negotiation and going to war - a mix of deterrence, containment and a return to maximum pressure, coordinated with our allies. That's likely where we will end up anyway and the longer we wait to pivot, the harder it will be.
As Sen. Robert Menendez, D-N.J., said, the Hanoi summit showed us "amateur hour with nuclear weapons at stake and the limits of reality-TV diplomacy."
Trump may see a personal political benefit to dragging out his love affair with Kim and dragging the world along with them on this Sisyphean effort. But the stink of this summit's failure and the danger of the North Korean threat are only increasing over time. No deal is better than a bad deal - but Trump getting played by Kim again and again is even worse.
