The Conservative Party is again in a state of self-inflicted crisis. On December 6th Robert Jenrick, an immigration minister, resigned from the government of Rishi Sunak. The cause was Mr Sunak’s attempt to implement a deal with Rwanda to deport asylum-seekers who arrive in Britain on small boats. Proposed legislation to stop the courts from blocking flights to Rwanda, as they have thus far, was too weak, Mr Jenrick said.

Mr Sunak, who has been in office for only 14 months, faces a widening rift in his party over an issue that blends questions of immigration and parliamentary sovereignty. There is no guarantee that his flagship legislation will pass. If that sounds familiar, it should. The trouble Mr Sunak has found himself in over the Rwanda programme has remarkable similarities to the crisis that engulfed the Tories under Theresa May during the 2016-19 fight to implement Brexit. Once again, a weak leader, radicalised backbenchers and a fundamentally madcap policy have resulted in political misery.

In both cases a fringe idea drifted into the mainstream. Leaving the EU was once a niche proposal, reserved for the comments section of the Telegraph and battier Tory MPs. Internal Tory manoeuvring saw it become official policy and, eventually, an existential cause. The Rwanda policy has had a similar trajectory. It started out as a wacky idea, conjured up at the same time as officials were wondering aloud whether to install wave machines in the Channel or deport people to St Helena, where Napoleon spent his final days. It became policy under Boris Johnson when he struck a deal with the government in Kigali in 2022. Mr Sunak adopted it, too, in order to boost his hardline credentials.

What was once a policy whim is now seen as a life-or-death matter for Tory lawmakers. “The fortunes of the Conservative Party at the next election are at stake,” Mr Jenrick wrote in his resignation letter. Suella Braverman, a hardliner whom Mr Sunak fired as home secretary on November 13th, declared on the same day that the party faced “electoral oblivion”. They are right to panic: Labour enjoys a rock-solid 20-point lead in the polls.

Political desperation makes for a bad negotiating hand. Having chained itself to Brexit via the referendum in 2016, Britain entered talks with the European Commission from a position of weakness. It agreed to settle outstanding bills to the EU of up to £39bn ($49bn) before discussions on a trade deal even began. Paul Kagame, Rwanda’s president, appears to have been taking tips from Michel Barnier, the EU’s Brexit negotiator. Britain has paid £140m upfront (1.3% of Rwanda’s GDP), regardless of whether anyone ever goes on a plane.

As happened with Brexit, the courts are front and centre. Britain’s Supreme Court ruled that the Rwanda scheme was unlawful on November 15th. Mr Sunak is attempting to circumvent its objections, using a bill introduced on November 6th. It would declare Rwanda (with which Britain signed a new treaty this week) a safe country; allow ministers to ignore interim decisions of the European Court of Human Rights that would prevent deportation; and prevent some appeals based on Britain’s Human Rights Act, among other laws. All this is justified by a single, familiar word: sovereignty. During the Brexit saga in 2016-19 the principle of parliamentary sovereignty became a battering ram in the hands of ministers; the same tactic is being used today.

As with Brexit, when only the hardest exit from the bloc was acceptable to purists, a Conservative government has found itself advocating an extreme position only to be told by its own side that it is not radical enough. Some MPs now want the government to disapply the European Convention on Human Rights (ECHR) entirely, as well as any other provision of international law that would prevent the deportations. Mr Sunak has balked at that, arguing that doing so “would collapse the entire scheme” since the Rwandans would pull out. The British government has contrived to make Mr Kagame, who won his last election with a slender 98.8% majority, a defender of international law.

Having pandered to his right-wing critics, Mr Sunak faces the prospect of being brought down by them anyway. By-election defeats have left the government with a beatable working majority of 56 seats; one person on the right of the party thinks that at least 40 MPs are willing to rebel. Moderate Tories are, as during Brexit, meekly accepting of a fundamentally radical idea. The people the policy is supposed to placate are the most upset. During a press conference with Mr Sunak on December 7th, a reporter for GB News, a news channel that has been strident about small boats, asked: “Migrants have told us they are laughing at the UK and its Rwandan policy. Are they right to laugh?”

The parallels with Brexit are not exact. Some in the Conservative Party want to force an election on the issue of small boats, just as Boris Johnson forced one on “getting Brexit done”. In 2019 that gambit worked to perfection: Mr Johnson won the biggest Conservative majority in four decades. Voters today do care about immigration, but the Labour Party’s enormous poll lead suggests that they buy the opposition’s argument that the Rwanda scheme is a sideshow. And whereas the Brexit referendum was a national decision, the Rwanda row is entirely of the Tories’ making.

Once an idea moves from fringe to centre, however, it can be hard to ignore. Attention is already turning to who will lead the Conservatives after Mr Sunak’s nigh-on inevitable defeat. A poll by ConservativeHome, a grassroots website, found that 70% of Tory members (who will end up picking the party’s next leader) want to withdraw from the ECHR altogether. Look around the outskirts of the party and you will find other schemes to loosen Britain’s international bonds. Why stay in the OECD’s agreement on minimum corporation tax? What about the World Health Organisation? Marginal views today can become mainstream causes tomorrow, at least in the Conservative Party. The Tory right grows hungrier with the eating. ■