Will Trump go to war over North Korea?

It's three a.m. in Washington DC and the President of the United States suddenly appears in the White House Situation Room. He's ranting about North Korea and 'Option B' and 'teaching those motherfuckers a lesson.'

Trailing after him is his military aide, clutching the briefcase that contains the black book and the nuclear code. The nuclear football. ('Option B', by the way, envisages a nuclear attack against both North Korea and China.)

According to a military official who's present: 'The rules say that if the President wants to order a military strike, then he can do it. Just like that. Doesn't need to consult anyone.'

It's all right. You can breathe out. It's a scene from a novel: 'To Kill The President', by Sam Bourne, also known as the award-winning Guardian columnist Jonathan Freedland. It was published this week (Harper Collins, £7.99), with astonishingly good timing, just as Donald Trump (the real one, this time) threatened North Korea with 'severe things' following what appears to have been Pyongyang's successful test of an inter-continental ballistic missile.

This is the same Donald Trump who boasted (on Twitter, of course) just weeks before his inauguration last January: 'North Korea just stated that it is in the final stages of developing a nuclear weapon capable of reaching parts of the U.S. It won't happen!'

Well, Mr President, it has happened -- or at least North Korea has now built a missile that appears to be capable of reaching Alaska or even Hawaii. (Why would it want to attack Hawaii? First, because the US maintains a substantial military presence there, and second, because it's a lot closer than the US mainland. Remember Pearl Harbor.)

But North Korea has not -- as far as we know -- developed a nuclear weapon small enough to be carried on an ICBM, nor one that is able to withstand re-entry into the earth's atmosphere. So the threat, while real, remains potential rather than actual.

Let us agree that the world would be a much better place if no one had any nuclear weapons at all. Let us also agree that we might sleep easier in our beds if Mr Trump had not reportedly asked a foreign policy expert last summer: 'If we have them [nuclear weapons], why can't we use them?'

If I were the North Korean leader Kim Jung-un, my question to Mr Trump would be this: 'How come it's OK for Israel to have nuclear weapons (although of course it still denies that it does have them); how come it's OK for the UK, France, Russia, China, India and Pakistan to have them; oh, and how come you, as leader of the only country in the world that has actually used nuclear weapons, get to decide who else can have them?'

Hypocrisy rules. All that North Korea wants is what we Brits like to call an 'independent nuclear deterrent.' (When countries that we don't approve of have the same thing, it's called 'weapons of mass destruction'.) In other words, it wants to be sure it can defend itself against possible attack -- and it wants to terrify its neighbours.

Mission accomplished, you might say, even before Pyongyang has shown that it does have both a nuclear weapons capability and the ability to use it. Its neighbours -- especially South Korea and Japan -- are duly terrified, and, understandably enough, they're extremely keen for the US to protect them.

So what might the unpredictable, impatient, under-informed and irascible Mr Trump do? If he bombs North Korea's missile sites, he risks hundreds of thousands of deaths as soon as Pyongyang retaliates against South Korea. (Nearly half the South Korean population lives within fifty miles of the border between the two countries.)

He already seems to have had second thoughts about relying on China to turn the screws -- surprise, surprise, President Xi Jinping turns out not to be prepared to act as the US president's poodle. (Trump tweet: 'Trade between China and North Korea grew almost 40% in the first quarter. So much for China working with us - but we had to give it a try!')

And as for internationally agreed sanctions, well, Mr Trump hasn't exactly gone out of his way to build strategic alliances, has he?

The US news network CNN has very helpfully compiled a handy list of all the issues on which Mr Trump has put himself at odds with the US's G20 partners.

Climate change? The US is in a minority of one.

Trade? From Canada and Mexico to China, Japan and the EU, the US is on the wrong side of the free trade fence. (Eg the just-signed free trade deal between Japan and the EU.)

Muslim travel ban? Even Theresa May has called it 'divisive and wrong'.

And even if the UN agrees to authorise a tightening of sanctions on Pyongyang (for example, by targeting Chinese banks that do business in North Korea), the precedents do not suggest that they would make a ha'penny-worth of difference. As Simon Jenkins pointed out in The Guardian: 'Cuba, Serbia, Iraq, Libya, Iran, Myanmar and Korea: history tells us that sanctions merely give longevity to entrenched regimes.' 

Which leaves diplomacy. Admittedly, it's been tried before, with only limited success. Years of talks involving the US, China, Russia, Japan, and North and South Korea halted Pyongyang's nuclear programme temporarily, but broke down when North Korea pulled out in 2009.

So it might be a good idea if North Korea's neighbours started by recognising that North Korea will not give up its nuclear weapons programme. As I wrote last April, the Kim dynasty are convinced that without it, they're as good as dead. After all, Saddam Hussein of Iraq and Muammar Gaddafi of Libya both gave up their nuclear programmes, and look what happened to them.

The best hope now is that China, Russia, and Japan will put their heads together and devise a new proposal to put to President Kim. And the best chance they have of getting anywhere is by making sure that President Trump is kept well away from anywhere where he could do real harm.

It's come to this: one ill-considered 6.30a.m. tweet from the Trump bed chamber could tip the Korean peninsula into open war. Appallingly, we are now reduced to relying on Vladimir Putin and Xi Jinping to find a way back from the brink.