"Our presidency has been debased by a figure who has a seemingly bottomless appetite for destruction and division and only a passing familiarity with how the Constitution works ... the Congress is utterly supine in the face of the moral vandalism that flows from the White House daily ... I do not think that the founders could have anticipated that the beauty of their invention might someday founder on the rocks of reality television, and that the Congress would be such willing accomplices to this calamity. Well … we may have hit bottom."
It is hard to overstate the sense of despair, disbelief and disgust the words express.
They cannot be dismissed, as Trump would no doubt have it, as the complaints of a political opponent.
We can only assume there are other senior Republicans who feel similarly but who do not have Flake's courage to risk their political futures if they tell the truth.
As it happens, this development comes hard on the heels of yet another Trump debacle – the off-again, on-again meeting with Kim Jong Un. The episode tells us a great deal about Trump's priorities and how his mind works.
We know Trump saw his meeting with the North Korean leader as a defining achievement of his presidency, and it did, in truth, offer a brief hope of an enduring peace on the Korean peninsula and a permanent relief from the threat of nuclear war.
But, important though these worthy goals may have been, they were clearly not the outcomes that were uppermost in Donald Trump's mind.
How do we know this?
Not just because of the pleasure he obviously derived from the (faintly ridiculous) suggestions that he should be awarded the Nobel Peace Prize, but because he had celebratory coins, bearing both his profile and Kim's, struck and photographed to mark the historic meeting even before it had happened.
The boost to Trump's ego was apparently so valuable and tempting that he could not forbear from claiming it even before the meeting had taken place – and now that the meeting may not after all happen – he is left, not with egg, but fragments of precious metals, on his face.
We should all be alarmed that major questions of nuclear war or not should be in the hands of someone whose priority is so clearly his own image.
Even more seriously, crucial decisions are being taken by someone who displays a complete ignorance of how other countries and leaders are likely to react when they are insultingly treated - taken for granted, threatened and pushed around.
If the Singapore meeting was to happen and be counted a success, it had to be preceded by the most careful preparation, to make sure both parties knew exactly what was in the other's mind.
We now know that what was in Trump's mind was the potential boost to his popularity, not the unresolved questions as to what Kim meant by de-nuclearisation.
And any chance Kim would be prepared to offer what the Americans wanted was certainly dashed by the crude threat that Kim, if he failed to come up to scratch, would suffer the same fate as Libya's Colonel Gaddafi.
Instead of those careful preparations, however, we had a re-issuing of nuclear threats and boasting by Trump about American military might.
That Nobel Prize now looks a long way away – and Senator Flake may soon find that he has some overdue company in the Republican party.
