"I have a very good brain," announced Donald Trump during this year's presidential election. Well, even a cursory glance at his Twitter account reveals a very different brain - that of an irritable pre-teen. His recent activity on the social media network shows the successful candidate to be bewilderingly self-deluded and prone to tantrums. Reason and tact are absent, vindictiveness and petty squabbling are very much on display. It's breathtaking to think that the future of the world's most influential superpower is to be held in such twitchy, pre-pubescent fingers.
To look at the President-elect on Twitter is to gaze into the abyss. This was his response to last week's death of Fidel Castro:
This is a chilling tweet. On so many levels. It is simple but has no clarity. The exclamation mark is revealing but ambiguous. Is it glee? Is it surprise? Is he conveying shock or delight?
With Trump - God help us - anything is possible.
This tweet, like so many others, appears to be the work of a skittish boy-brain. It lacks only an "OMG" as he squeals with excitement to scribble his reaction to breaking news.
During the election campaign, Trump received praise for his spontaneity and unrehearsed manner. But this was only because the public was so catastrophically tired of pontificating politicians. Really, anything vaguely approaching normal human communication would have been a welcome change. Many even forgave the alarming content of his speeches, so relieved were they at actually hearing someone seemingly speak their mind.
But on the world stage, at least some form of diplomacy is required when responding to significant events. The Donald simply does not possess this skill. To have such a crass and clueless individual in The White House is a devastating prospect.
Like a child, but minus the sweetness, Trump also has a critically short supply of self-awareness.
A week ago he was in negotiations to meet with the bosses of The New York Times, a newspaper which - in the light of the Trump / Billy Bush sex tape and amidst mounting allegations of misconduct - had quite sensibly articulated serious concerns about the quality of the Republican candidate.
The President-elect, unwisely, gave his Twitter followers the lowdown:
"The terms and conditions were changed", complains Trump. "Not nice" adds the wailing man-child as he stamps his foot and throws his toy bulldozer to the floor.
OK, let's just rewind a couple of months to the President-elect's campaign promises.
Using Twitter again as his favoured medium, Trump proclaimed to his followers "we must build a wall" and "Mexico will pay for the wall."
Terms and conditions have now changed.
During the presidential debates he pointed at Hillary Clinton and promised he would "appoint a special prosecutor to look into your situation."
Terms and conditions have now changed.
On his campaign website he stated that "on day one of the Trump Administration we will ask Congress to deliver a full repeal of Obamacare."
Terms and conditions have now changed.
Right. So it's one rule for The New York Times who were trying to set up the basic conditions for a face-to-face meeting, but another one entirely for the man who is actually making recorded statements about something infinitely more significant - the future direction of the world's most powerful nation.
With Trump, like the formative boy who forgets what he's said or twists past statements into something new, words are simply throwaway objects, guttural noises that can be spouted and withdrawn in an instant. He is numb to the significance of speech - except when it is used to criticise him.
Only then does it hurt.
We saw this on the campaign trail when a steaming Trump brushed off his sexual accusers as "horrible horrible liars." Just days before, he had held up Bill Clinton's accusers as brave beacons of truth. The car-crash hypocrisy is truly mind-boggling.
Childlike, he is super-sensitive to criticism but immune to the havoc wreaked by his own aggressive outbursts. In The Donald's pre-teen world, double-standards abound.
In retrospect, we can see that his repeated promises to a deluded nation were mere flights of fancy, puff pieces used to hoodwink voters and get him into the Oval Office. There is no principle, no guiding philosophy, only false pretences and empty rhetoric. What is heralded as concrete policy one day is jettisoned to the dustbin of history the next.
Amazing. Excruciating. And potentially disastrous. We will never know where we stand.
True, many of us will be breathing a sigh of relief that Trump's toxic policy promises appear open to compromise, or indeed reversal. But this is perilous territory and for politics it's a game-changer. Sure, politicians lie, but usually they are held accountable. Trump, even before taking office, has abandoned the divisive pillars upon which he was elected - and yet he angrily dismisses mutterings of accountability as the lies of a "crooked media."
Trump has the backbone of an amoeba, the skin of a chameleon. Poisonous words spill forth, sink into the sand and are left to rot. On Twitter and elsewhere, these words remain, testimony to an unstable and insecure President-elect who is stunningly oblivious to the power of language.
He clearly does not have "a very good brain." He is stuck in arrested development, a little boy-bully who has got the top job, who can say whatever he wants, and none of us will ever have a clue if he means it.