There is no mystery about Suella Braverman’s views on the European convention on human rights. The home secretary wants Britain to withdraw from it. And she doesn’t care who knows it, even if that means ignoring the evidence, trashing cabinet collective responsibility and breaching the ministerial code once again. Withdrawal is what Braverman advocated when she ran to be leader of the Conservative party in the summer contest won by Liz Truss. It’s what she advocated “personally” as home secretary at a Tory party conference fringe meeting in October, before she was forced to resign two weeks later for a separate breach of the ministerial code. And it’s what she came super-close to repeating this week when, home secretary once more, she endorsed a Centre for Policy Studies (CPS) report on Channel migration crossings that calls for withdrawal as an option. There is, though, a major political problem with Braverman’s idée fixe, in and out of government, of withdrawal from the convention. Withdrawal from the European human rights process, of which Britain was a founder under the postwar premierships of Clement Attlee and Winston Churchill, is not actually UK government policy – and Braverman is a senior member of that government. Nor was withdrawal part of the Conservatives’ 2019 election manifesto, which Rishi Sunak says he regards as his government’s mandate. It was not part of the remit of the human rights review – which had been promised in the manifesto – that was established by the Johnson government in 2020 under Sir Peter Gross. It formed no part of the 520-page report published by Gross the following year, which concluded that Britain’s human rights laws were “generally working well”. Withdrawal is not part of the bill of rights that was launched by Dominic Raab during his first stint as justice secretary in June either. Under this far-reaching piece of human rights law reform – which flies in the face of the Gross review – Britain would nevertheless remain a party to the European convention and British citizens would retain the right, which they have had since 1966, to take cases to the Strasbourg court. Raab’s plan remains paused in the Westminster legislative process. It was halted by Liz Truss in September amid reports that officials considered it “a complete mess”. It has not yet had its second reading in the Commons and it has yet to be considered by the House of Lords. But it is due to come back to parliament soon. As recently as 22 November, Raab told MPs that, when it does, “we are staying as a party to the ECHR”. Not if Braverman gets her way, however. Raab’s commitment is now the subject of an internal Tory party tug of war, in which the home secretary, under pressure over Channel migrant crossings, wants to break with the human rights convention altogether in order to fast-track plans to deport Channel migrants to Rwanda. Withdrawal has long been a goal of the Tory party’s most rightwing nationalists. Braverman is therefore placing herself at the head of a revolt with plenty of potential supporters. Already this week, Sunak has backed down in the face of backbench attacks on housing policy and onshore wind turbines. Braverman’s decision to write a supportive introduction to the new CPS report, co-written by Theresa May’s former aide Nick Timothy, is thus a high-stakes move on another front. If she loses, it may be a resignation issue, which may cement her claims to be the leader of the party’s nationalist wing. If she wins, Raab’s future would be the one in doubt. But there are bigger issues at stake in this argument than ministerial personalities. There are at least three of these. The first is Sunak’s diminishing authority over his government. Braverman has clearly interpreted her reappointment in October as proof of the new prime minister’s weakness. He has to balance the Tory party’s many factions. She is driven by faction. He therefore needs her more than she needs him. So she breaks the rules and conventions of office – something Braverman did as attorney general too – to suit herself and her faction. So far, she has been able to get away with it. This does not merely emphasise Sunak’s weakness as a party manager. It also underlines how the Conservative party is struggling to stem the decline in political trust. Sunak has not yet tried to put his personal stamp on the ministerial code, and he has not appointed an ethics adviser. He badly needs to do both. Otherwise he is at risk of presiding over a period of sleaze scandals such as the PPE inquiry and resignation honours lists. The final months of Tory government will not improve the party’s election chances if it is seen to be a factional free-for-all taking place in an ethical desert. The second is the way an often chimerical argument about human rights laws encapsulates and stimulates the Tory party’s haphazard retreat into a bubble of English exceptionalism. Whether it is expressed by Braverman or by Raab, the common threads of this are a bogus sense of British victimhood (exemplified by the delusion that Britain is uniquely affected by migration), a belief in greatness frustrated (exemplified by the lies of Brexit), and an impatience with conventional wisdom in favour of reckless contrarianism (exemplified both by Dominic Cummings and Liz Truss). Frustratingly for the Conservatives who think this way, their doctrinaire belief in the nation as the sole arena of effective governance has developed at the same time as their own party has been consciously reducing the resources of the nation state over the past half-century. It means they long to create a country they have themselves done so much to destroy. The weakening of the Conservative party’s commitment to the rule of law is the final example. Margaret Thatcher used to invoke the rule of law at every turn. If she did that today, many in her party might be tempted to view her with suspicion. The former attorney general Dominic Grieve pointed out this week that today’s ministers, unlike their forebears, display “a persistent, almost endemic frustration with legal constraints”. The government, said Grieve, was evolving “a novel constitutional principle: that governments enjoying the confidence of a parliamentary majority have essentially a popular mandate to do whatever they like and that obstruction of this is unacceptable”. This is where the crisis in the Channel meets the pathological victimhood of so much of the modern Tory party. The compulsion to deport migrants to Rwanda is the latest case in which ministers see the law as a hostile opponent. Braverman’s attitude is indicative of a party at ease with the judges cast as “enemies of the people” and with human rights dismissed as the plaything of lefty lawyers. Raab’s bill of rights, for which there is negligible demand outside earnest Tory thinktanks, embodies the same approach. A generation and more after Thatcher, it is now the Conservatives who chafe against the rule of law and Labour who seems more comfortable with it. Martin Kettle is a Guardian columnist