First, a confession. One that relates to the current threat facing our democratic way of life and which involves a decision I made nearly 15 years ago. It turns on the unlikely name of Brian. In January 2004, I covered for this newspaper the publication of the Hutton report into one of the most vexed aspects of the Iraq war: the death of the scientist and weapons inspector David Kelly, and the accusation by the BBC that Tony Blair’s government had “sexed up” its dossier on the threat supposedly posed by Saddam Hussein. Lord Hutton exonerated the government entirely, coming down hard on the BBC. Like many other opponents of the invasion of Iraq, I branded the whole exercise a “whitewash”.

Jo Swinson pairing row: Conservatives admit chief whip asked MPs to break arrangements Read more

But in the closing paragraphs of the piece, I went further. Who exactly was this bewigged man who had cast a complex dispute so neatly into black and white? What great, mystical insights did he have, really? Wasn’t it possible that he had biases of his own – an instinctive faith in the state and a low regard for journalism, perhaps – that had proved very convenient for the government that had selected him for this task? “These people are human beings like any other,” I wrote. “It seems worth remembering that, before he was a law lord, the judge was plain Brian Hutton.”

I thought I was bravely shattering the mystique of the priesthood we call the judiciary – he’s just a man called Brian! – but afterwards a few people I respected , people no less hostile to the Iraq war, took me to task. They warned that I had taken a small step down a slippery slope, disparaging the system that upholds the rule of law. It’s not perfect, they told me, but it’s all we’ve got.

This week I remembered the wisdom of that advice. It came back to me first with the reaction to the Electoral Commission’s findings that the Vote Leave campaign broke the law during the 2016 referendum, through undeclared spending and illegal co-ordination with another group, BeLeave. The commission imposed a punitive fine of £61,000, in part because Vote Leave refused to co-operate fully with their investigation: in three months, the commission made five attempts to interview the group, each time without success.

A prominent leaver, the Labour MP Kate Hoey, casually dismissed the commission’s findings. She hadn’t bothered to read the report, she admitted, not least because she had no faith in the commission itself: “Most of the people on it were active remainers,” she told BBC Radio 4’s World at One.

Vote Leave had already shown similar contempt, by leaking a partial version of the commission’s conclusions before publication. The group’s former chief executive, Matthew Elliott, echoed Hoey by accusing the commission of having its own “highly political agenda”.

This approach has been effective. There are few demands for Boris Johnson and Michael Gove to be called to account for the illegal activities of Vote Leave, even though Johnson was its most public face and Gove served as its co-chair. To say nothing of Liam Fox, Iain Duncan Smith, Priti Patel and new Brexit secretary Dominic Raab, all of whom served on its key committee.

Play Video 1:51 Anti-Brexit Tory MP Anna Soubry asks: who runs the country? – video

Instead, too many seem to have accepted, even implicitly, Vote Leave’s depiction of the Electoral Commission as just another partisan body with an opinion. It was striking to hear the World at One presenter Sarah Montague repeatedly refer to “these allegations”, when they were, in fact, the findings – the verdict – of the statutory body charged with protecting the integrity of UK elections. It is not an allegation that Vote Leave broke the law. It is now a fact.

There is something alarmingly Trumpian about all this. The US president similarly dismisses the core institutions of American democracy as no more than partisan players, to be cheered when they help and booed when they hurt. Robert Mueller was a trusted figure in US law enforcement for decades, universally admired for serving without bias. But Trump happily trashes Mueller’s inquiry as a partisan, pro-Democrat “witch-hunt”. He has done the same with his own intelligence agencies – trusting them less than the word of Vladimir Putin – as well as the FBI, the Department of Justice, the courts and, of course, the “fake news” media.

The effect, as the Vote Leave whistleblower Shahmir Sanni put it so eloquently this week, is to “instil doubt in the public towards the institutions that are meant to protect them”. We’ve got used to seeing that in the US, as Trump toils daily to discredit the bodies that were previously trusted to serve as referees, but now we’re seeing it in Britain too: an attack on the rules by which the democratic game itself is played and on those who enforce them.

We should hardly be surprised that they’re now ready to turn on democracy and the rule of law

This is the context in which the apparently inside-the-Westminster-fishbowl scandal over “pairing” should be viewed. MPs are right to be outraged by the dishonesty of the Tory chief whip, Julian Smith, effectively promising the Lib Dem Jo Swinson she could skip a crucial vote to look after her new baby, only to break the promise that her non-vote would be cancelled out by a non-vote on the Tory side. Theresa May insists it was all an “honest mistake,” but there are well-sourced reports that Smith ordered at least three other MPs to break their pairs and that he spoke openly about the move. His conduct was a breach of the basic trust and civility without which parliament cannot function.

But it is also yet more evidence of what the sulphuric acid of Brexit is doing to corrode our democratic machinery. At its most modest, it is ministers blithely dumping long-established parliamentary conventions, designed to ensure the minority are not trampled underfoot. More dramatically, it’s the readiness of supposed conservatives to risk or even destroy institutions they themselves would once have seen as central to the country’s identity.

Hardcore Brexiteers have already demonstrated their willingness to jeopardise peace in Northern Ireland; to threaten the independence of the judiciary, rebranded as “enemies of the people”; to buckle on the supremacy of parliament; to disregard industry and commerce (“fuck business”); and to imperil the union itself. Given all that, we should hardly be surprised that they’re now ready to turn on democracy and the rule of law. But we need to heed the warning. The system we have is far from perfect – but it’s all we’ve got.

• Jonathan Freedland is a Guardian columnist