Up until very recently this was a very real possibility. Remote, to be sure, but still very real. Certainly it was the most likely of all the nuclear conflict scenarios.
It is self-evident that no country was more at risk in this détente, no people more threatened, than South Korea, with whom the North was still technically at war until just days ago.
Now, thanks at least in part to Trump's crazybrave "diplomacy", that threat has almost certainly abated.
In fact the two Koreas are now closer than they have ever been in more than half a century, a prospect that would have been unthinkable even just six months ago.
Broadly speaking, there are two possible explanations for why this has happened. One is that Trump is so erratic and incompetent that America can no longer be relied upon to provide some semblance of global stability. So feuding nation states who might once have relied on the US as a kind of safety net have suddenly realised they have to sort things out among themselves.
It's a bit like the standard fairy tale trope of warring siblings learning how to work together when mummy and daddy go Awol.
The other is what is known as the "madman theory", a geopolitical strategy that is literally so crazy it just might work.
Basically, the idea is to let your enemies think that you are so irrational, so unhinged, that you are capable of any act, no matter how destructive.
The term was coined by Richard Nixon during the Vietnam War and the concept dates back to Machiavelli, who observed in 1517, it could be "a very wise thing to simulate madness".
If this is Trump's tactic it is the performance of a lifetime.
One minute he is bombarding Kim Jong-un with belligerent late-night tweets, the next he is barging into media scrums offering to be the first US president in history to meet the North Korean Supreme Leader. The world hasn't seen such hardcore method acting since De Niro in Raging Bull.
So is this extraordinary and sudden détente between the two Koreas, which has brought the world back from the brink of a potential nuclear war, been the result of Trump's deliberate strategy or accidental buffoonery?
Of course there can be only one true answer, and that is as follows: Who cares?
When it comes to world peace, success isn't measured in 140 characters. It's measured in, well, peace. And that seems to be what we have now.
So why the hell shouldn't Donald Trump get the Nobel Peace Prize? Whether he knows how or not, he's done more to stabilise the Korean peninsula than any other US president.
And he would certainly be no less worthy than plenty of other Nobel Peace Prize recipients.
Henry Kissinger got one in 1973 despite being heavily involved in the Vietnam War and then negotiating a ceasefire that failed. He was also implicated in a couple of coups in South America and supported Pakistan in its war against Bangladesh in which it was accused of genocide.
And of course recently we have been reminded that Burmese leader Aung Sun Suu Kyi got one in 1991 only to be now implicated in the genocide and/or ethnic cleansing of more than 100,000 Rohingya people in Myanmar.
The South African president FW de Klerk was given one alongside Nelson Mandela in 1993, despite de Klerk being a lifelong supporter and enforcer of apartheid until his sudden conversion to equal rights for black people when it became clear the tide was turning.
And the following year Yasser Arafat was given one alongside his Israeli counterparts, despite his role in founding what was to become a terrorist organisation.
Even as recently as 2009 Barack Obama got one but no one could really say what for. The official reason was "extraordinary efforts to strengthen international diplomacy and co-operation between peoples", which could equally apply to just about every world leader to the left of Hitler and the right of Pol Pot.
Certainly it's fair to say the five million displaced people around Syria aren't very much at peace, although maybe the hundreds of thousands of dead are.
And of course the founder of the Nobel Peace Prize himself was a warmonger, or at least sold warmongers their weapons. Apart from inventing dynamite and various other explosives — the making of which accidentally killed his younger brother — Alfred Nobel's legacy was to turn the family business into an arms manufacturer.
Indeed, it was only after reading a mistakenly published obituary of himself that described him as "the merchant of death" that the great industrialist and inventor set aside his estate for the awards that now bear his name.
No matter how unworthy Trump is of a Nobel Peace Prize he is almost certainly far more worthy than the man who founded it, and many others who have won it. It is odd that so few people know this.
And so bestowing such an honour upon such a strange, abrasive and maybe even dangerous man may well be "idiotic", as some commentators have suggested, but even more idiotic is the outrage against it.
Madmen have been as ever-present through history as morons and messiahs. The only thing more dangerous is the fools who forget them.
