In the history of the world, there has never been anyone as guilty of an alleged offence as Donald Trump is of inciting the insurrection in Washington DC on 6 January 2021. There has never been a case more clearly proven in “cold, hard, facts.” And in the history of the world, there has seldom been a response as venal, craven and expedient as that of 43 Republican senators who could not bring themselves to vote to convict him. Their names will live on forever in infamy.

It is well known that a conviction in an impeachment case in the USA requires a ‘super-majority’ – that is a two-thirds vote in favour. Something similar to this is common in the constitutions of other countries worldwide, where foundational matters of change (like the amending of a constitution itself) must have this great majority in support. That is understandable. The more people agreeing on something, should give it a strength approaching indisputability.

But complete agreement – even on matters of great import – is perhaps a false dream. Consensus has become a fashionable term of late. We can only go forward on something, devotees of consensus say, if we all agree. But, respectfully, I contest that; for consensus is a chimera. And it can never deliver when boldness in decision-making is called for. Because not everyone is bold. Or informed. Or wise. Witness the American senators.

Imagine if, given the onset of the Covid pandemic, our government’s response was to have waited until consensus was achieved on a plan of action. There would have been adherents to herd immunity in opposition, libertarians would have contested the lockdowns, anti-vaccers would have said no to mass immunisation, and we would have been in a much worse place than we are now. New Zealand’s response to Covid, acknowledged as the most effective in the world, is the result of decisive action taken by a few on our behalf, and supported by the best practise in population health science.

Why, even on matters as central to the human condition as those outlined in the latter half ten commandments, we cannot all agree. Sure, the first five can be overlooked by adherents of other religions, and that is surely their right, but from number six onwards, they matter to all of us. Number six: ‘Honour thy father and mother’ – do we all do that? No, not always.

‘Thou shalt not kill’ (or murder, in some versions). Kill what? – plants, animals, humans? For the first, does this mean we all become fruitarians? Even as a vegan, you have to kill a cabbage to eat it. And further, are we all commanded to be vegetarians at the very least? As for killing humans, there would be many military men, proponents of the death penalty, or the odd psychopath who would argue that this must be done on occasion.

‘Thou shalt not steal’, or ‘commit adultery’. These things happen with regularity. There is no consensus – nor will there ever be – on even these vital matters.

Consensus, when it is reached, must always be a watered-down compromise. Because if everyone agrees, a lowest-common denominator (often of ignorance) must be reached. As Abba Eban, the Israeli diplomat said, “A consensus means that everyone agrees to say collectively what no one believes individually.”

Consensus also relies on prevailing conventional wisdom, which we all know is seldom wisdom at all. It simply does not allow for the iconoclastic. “When there's ever a breakthrough, a true breakthrough, you can go back and find a time period when the consensus was 'well, that's nonsense!' so what that means is that a true creative researcher has to have confidence in nonsense,” said Burt Rutan, the American space scientist. How true.

And a last word, but sadly too late, for those ten more America senators who could at least have joined the super majority, from Joseph Brodsky, their compatriot poet: “An ethical man doesn't need a consensus of his allies in order to act against something he finds reprehensible.”