There are two possibilities: either President Trump was as ignorant after his June 12 meeting with Kim Jong-un about what North Korea has in mind when it pledges “complete denuclearization of the Korean Peninsula” as he was in March when he brushed aside warnings from his aides and rushed to accept Kim’s invitation to meet. This would mean that in the intervening three months he learned nothing about the past quarter-century of failed efforts to stop North Korea’s nuclear program and genuinely believes he accomplished something in Singapore.

Or the president knows that he got nothing. In that case, when he bragged on his way home that “this should have been done years ago” and later tweeted “There is no longer a Nuclear Threat from North Korea,” he was simply being fraudulent in the way that works so well for him at home. Stripped of its made-for-TV trappings—the walk, the flags, the solemn handshake, and the breathless talk of history being made—nothing was actually agreed to at the summit. Evidence that there had, in fact, been no meeting of the minds came with whiplash speed. In just over three weeks North Korea was accusing the US, which had not changed its position, of “gangster-like” demands. Call it Fake Diplomacy.

Which is more dangerous—someone so convinced of his abilities and so lazy that he would walk into such a negotiation without knowing even the tiny bit of history (sketched in the box at the bottom of this page), or someone willing to offer the world a bald-faced lie? Someone who doesn’t try, or someone who doesn’t care about the actual outcome as long as he can sell a short-lived story of personal success and move on?

Unpreparedness risks costly mistakes, such as the ones Trump made at this meeting. Bluster and sloppy, unthinking language risk being misinterpreted by both adversaries and allies as being serious when it isn’t or, worse, brushed aside as a bluff when it isn’t. Historians still debate how great an effect Secretary of State Dean Acheson’s speech placing South Korea outside the US defense perimeter had on the decision made by Kim Il Sung, Stalin, and Mao to launch the Korean War in 1950.

The phrase “complete denuclearization of the Korean Peninsula,” which got Trump so excited back in March and which he continues to mistranslate as “they are willing to de-nuke,” was, as the box reveals, first used by North Koreans twenty-six years ago. To them, it has always meant that North Korea would denuclearize after the United States walks away from its defense alliance with South Korea, removes its troops from the Korean Peninsula, withdraws the nuclear umbrella that now deters an invasion of South Korea, signs a peace treaty to end the Korean War, removes nuclear-capable weapons (or perhaps its entire presence) from an undefined perimeter of Northeast Asia, and ends other “anti-DPRK hostile policies,” presumably including…