The debate about what has caused his shortcomings is largely beside the point. It may be that he is mentally ill, suffering from an inherited personality defect or from the onset of dementia.
It may be that his defiance of the normal standards of decency is the product of his upbringing as the son of a wealthy and domineering father or of the limitations of a billionaire's lifestyle.
It may be that he is simply what we see – an embryonic fascist, a self-absorbed bully and narcissist, persuaded of his own "genius", and harbouring a range of really unpleasant views about race, women and the plight of those in society who need help.
But whatever the explanation, we are lumbered with him. The only question now is what can be done about that. Sadly, the only people with the power to take action show no sign of willingness to do so.
The Republican majority in Congress could impeach him – a number of grounds offer themselves and the Mueller inquiry into Russian involvement in Trump's election might add to that number - or simply remove him on account of his inability to fulfil the role.
But the Republicans are in hock to billionaire donors who are the ones who really pull the strings.
The one ground for optimism is that Trump has already delivered to those billionaires the benefit they were willing to pay for – massive tax cuts for the wealthy, achieved at the cost of cutting the help and health care available to the poor and sick.
It may be that, with the tax cuts in their pockets, those wealthy Republican donors will see Trump as disposable, and will therefore drop their threat to Republican Congressmen of reduced funding if they don't support Trump.
There is one further possibility which I hope is not too fanciful. Trump himself may decide to review the question of whether the game is worth the candle. By all accounts, he is not enjoying the role and gets away from the White House whenever he can.
It may be starting to dawn on him that being president may deliver the fame and recognition he craves, but that the spotlight on him also means that his every misstep and failing is magnified.
There is no escape for him – the longer he stays in the White House, the more certain it is that his public image and reputation will be trashed; his plight is rather like that of an actor in a leading role who, having forgotten his lines, is nevertheless compelled to make his entrance on the stage.
He may now realise that he is destined to go down in history as a disaster, as the worst ever president, as an embarrassment to his country and to America's allies.
Why, he might ask himself, prolong the agony?
Why run the risk of being impeached, or removed for incompetence, or (if the polls are accurate) being voted out of office?
Why not choose the moment, and the pretext, for stepping down?
We can but hope.