Democracies run on trust. Luckily there’s an ancient, untapped source

If you wanted to lose an English audience, it would be hard to find a more effective way than to tell them that religion is important to democracy. For a substantial minority, religion is simply a toxic phenomenon whose malign effects range from sexual repression to suicide bombers without ever straying into kindness or compassion. In our secularised times, a majority believe it can’t possibly have any use or relevance in the modern world.

By extension, anyone who thinks debate about religion really matters is liable to be considered a bit of a weirdo. That is why campaigns against the bishops in the House of Lords have scarcely any more traction than campaigns in their favour.

But both sides are wrong. Religion does supply some nutrients that democracies need to survive. I came to this conclusion while listening to Charlotte Knobloch, who survived the Holocaust as a child hidden on a farm in rural Bavaria, and is now the leader of the Bavarian Jewish community. She was talking at a conference in Cumberland Lodge, in Windsor Park, on moral and spiritual defences of democracy: this is a woman with a very German, serious attitude towards ideas – and three large bodyguards, to remind us what some ideas can lead to.

She quoted a supreme court judge who had written at the height of the Baader Meinhof terror attacks in the 1970s that liberal, secular democracy arises from conditions that it cannot itself guarantee. This is a profound and disturbing remark that undermines all the confidence of westernising globalists who believe our values will naturally spread across the world as soon as people realise they can choose them.

In particular, she said, liberal, secular democracy depends on trust. People need to trust the institutions of the state, the political class needs to trust the people, the media have to be both trusted and trustworthy, and people need to trust each other. All these forms of trust have been eroding in this century, and populist movements of all kinds are both a product of this erosion and a further cause of it.

The people chanting “Liar!” and “Nazi!” at Anna Soubry are both expressing their own alienation from the political order and encouraging it in others.

The problem thus becomes one of restoring trust on all levels. The difficulty is that we don’t know how to do this for institutions. We maintain and restore trust by being ourselves trustworthy and punishing those who are not. This is possible, though hard enough, on a personal level. But society is made up not just of personal interactions. It operates through institutions – and when they are broken and untrustworthy, they are even harder to fix. How does an institution repent convincingly? The example of the Catholic church with child abuse shows how hard this is for an institution that has forfeited trust. How can we convincingly punish the representatives who fail and betray our trust? In this country we generally end up giving them seats in the House of Lords.

Religion, despite its chequered and sometimes shameful record, can at least give us something to think about here. Because religions attribute to our actions a significance beyond the calculation of individual advantage and consequence.

Something that works like religious faith is the only way to establish the kind of structures of trust and the links between personal and collective morality that democracies need if they are to work. Knobloch said religions offered continuity and community, and these are other aspects of the same fundamental linkage. Only by imagining – in the teeth of much evidence – that all of us deserve to be judged impartially and fairly, and in some sense ultimately, will be – can we – move towards a society where this is almost true.

Of course religions are irrational. But so are all forms of social organisation. The only perfectly rational calculator of their own interests is a sociopath – and the sociopath is unable to calculate the best interests of anyone who is not a sociopath. Civilisation depends on people following rules that they cannot entirely understand or justify quite as much as it needs people to question them.

Rational self-interest will not do the trick. That is what gave us the present crisis. The cure can only be faith in something better than the calculation of advantage, whether this is Christianity or the American constitution. It hardly matters which: what matters is the structure of shared practice and belief which gives a shared moral significance to our actions, so that both rulers and ruled are judged by the same laws. And in Donald Trump’s case, this should ultimately be the criminal law.

• Andrew Brown is a Guardian writer and an author