“I’m speaking with myself, number one.” The year is less than three months old, but for our planet these may already be the six most terrifying words uttered in 2016.

And no prizes for guessing who uttered them, in an interview this week with the cable channel MSNBC. Donald Trump, property mogul, reality TV celebrity and heavy favourite for the Republican presidential nomination, was being pressed on who was advising him on a foreign policy that thus far has consisted of feel-good platitudes, positions on issues that can change in 24 hours, and insults and threats to anyone or any country deemed to stand in America’s way.

Foreign policy is an area where US presidents, so constrained by the checks and balances of domestic politics, have largely unfettered power. For weeks now, the man who aspires to have his finger on the nuclear button has promised to unveil his team of advisers.

Make no mistake: should the once unimaginable come to pass and Mr Trump find himself in the Oval Office, he will have advisers. No president, however expert in international affairs, can keep abreast of the intricacies of a complex world, let alone a world as disorderly and dangerous as this one. Decisions of war or peace, summits with Russia and China, and the delicate matter of alliance maintenance, are no place for giant ego trips, unbiased by any knowledge of the facts.

Indeed, were it any other frontrunner in Trump’s position, Republican foreign policy luminaries would long since have been discreetly stressing their closeness to the candidate, as they jockey for plum national security jobs in a new administration. But that hasn’t happened.

People who will flee America if Donald Trump wins Show all 8 1 /8 People who will flee America if Donald Trump wins People who will flee America if Donald Trump wins Miley Cyrus 'God’ he thinks he is the f***ing chosen one or some shit! … Honestly f*** this sh*t I am moving if this is my president! I don’t say things I don’t mean!' Jemal Countess/Getty Images People who will flee America if Donald Trump wins Whoopi Goldberg 'I don’t think that’s America. I don’t want it to be America. Maybe it’s time for me to move you know' People who will flee America if Donald Trump wins Samuel L. Jackson 'If that mother**er becomes president, I’m moving my black ass to South Africa' People who will flee America if Donald Trump wins Raven Symone 'My confession for this election is, if any Republican gets nominated, I’m gonna move to Canada with my entire family. Is that bad? I already have my ticket. I literally bought my ticket, I swear' People who will flee America if Donald Trump wins Cher 'If he were to be elected, I'm moving to Jupiter' People who will flee America if Donald Trump wins Neve Campbell 'I’m terrified. It’s really scary. My biggest fear is that Trump will triumph. I cannot believe that he is still in the game ... [I'll] move back to Canada' People who will flee America if Donald Trump wins Jon Stewart 'I would consider getting in a rocket and going to another planet, because clearly this planet’s gone bonkers' People who will flee America if Donald Trump wins Randy Blythe 'He could just be a clown. If he is the president, though, I am leaving America 'till he's gone'

Instead Mr Trump brags vacuously about getting “the best people”, so far unidentified. And as he continued in that surreal performance on MSNBC, “I have a very good brain… my primary consultant is myself, and I have a good instinct for this stuff.”

In the meantime, the only names that have surfaced are those of Jeff Sessions, the arch-conservative junior senator from Alabama, with some experience on the Armed Services Committee, and Mike Clovis, a retired US Air Force colonel and a member of Trump’s tight-knit inner campaign circle. And there’s a reason for the silence. Most Republican national security honchos won’t touch him with a barge pole.

More than 120 have now signed an open letter, declaring themselves “united in our opposition to a Donald Trump presidency”. These gentlemen, of course, should not be regarded as infallible. Many were enthusiastic backers of the 2003 invasion of Iraq, arguably the US’s biggest foreign policy blunder of the last 100 years, Vietnam included. But their critique is withering.

Mr Trump is “fundamentally dishonest,” they write. “He swings from isolationism to military adventurism within the space of one sentence… his vision of American influence and power in the world is wildly inconsistent and unmoored in principle.” Then there is the candidate’s “admiration for foreign dictators”, his violent anti-Muslim rhetoric, his backing of torture, his threats against allies and his readiness for trade wars.

Anonymous Declares Total War on Donald Trump

And yes, he’s put the boot in on almost everyone: France, Germany, Britain, Belgium, Japan, Saudi Arabia, South Korea, all of them longstanding US allies.

Everyone too knows about the Trumpian rants against Mexican immigrant “rapists” and his vow to build a Great Wall of Trump along the southern US border, paid for by Mexico.

US rivals like China and Iran obviously get no quarter (though some of his kindest words are for Vladimir Putin). Climate change is a hoax, he maintains, while global warming is a concept “created by and for the Chinese to make US manufacturing non-competitive”. Could someone explain this last?

Believe it not, however, there is a method to the madness. Only to an extent is Mr Trump making it up as he goes along. Strip away the bombast, the insults and the self-adoration, and his basic views have a long consistency and have ample precedent in US history.

Back in the mid-19th century, the Know-Nothing movement railed at the Irish and German immigrants who were threatening the very essence of America, much as the Mexicans and Muslims of today’s Trumpian demonology. In the 20th century, plenty of politicians and celebrities admired dictators and wanted to pull back from the world: think Charles Lindbergh and his pro-Nazi proclivities, or Robert Taft, the conservative senator who opposed US aid for Britain in 1940, and subsequently made three unsuccessful bids for the Republican presidential nomination.

Or take a interview Mr Trump gave to Playboy magazine in 1990 when his vaulting ambitions were already evident. A President Trump, he said, “would believe very strongly in extreme military strength. He wouldn’t trust anyone… he’d have a huge military arsenal, perfect it, understand it. Part of the problem is that we’re defending some of the wealthiest countries in the world for nothing... We’re being laughed at around the world, defending Japan.”

The self-same themes resound in 2016. In doctrinal terms, Mr Trump could be described as nativist, mercantilist and neo-isolationist. Put more simply, he is viscerally anti-immigrant and believes America is a soft touch, ripped off by the Chinese especially but by its other trading partners too.

And third, he believes America should cut back its involvement in the world, sheltering behind a mighty military apparatus that would crush any aggressor like a fly. But if wealthy countries like Japan, Germany and Korea want America to defend them too, they should pay for it instead of freeloading, as Mr Trump claims they do now.

Whether these views would survive his first Oval Office collisions with global reality is anyone’s guess. Maybe the deal-making skills he vaunts would come into play. Maybe those skills would produce a more even-handed US approach to the Israel-Palestine crisis. Who knows?

But right now all we have is words, and on that basis a Trump presidency is a truly scary prospect. A couple of weeks ago, The Washington Post columnist Anne Applebaum warned that we may be just three votes away from the disintegration of the post-war international order: the election of Trump, Brexit, and a President Marine Le Pen in France.