“OPPENHEIMER”, which won seven Oscars at the Academy Awards on March 10th, is a film about hubris and regret. Cillian Murphy plays the titular American scientist who builds the atomic bomb that will end the second world war. Then the Soviets get its secrets. An arms race begins; he is tortured by visions of missiles streaking through the sky. “He talks about putting the nuclear genie back in the bottle,” scoffs a rival. The prospect of Armageddon can make you question your career decisions.

In recent years Tory ministers have been conducting their own experiment with the nuclear physics of the British constitution. The cognoscenti call it a restorationist agenda that asserts the primacy of a sovereign Parliament over subordinate institutions, and of elected politicians over unelected officialdom. To less sophisticated folk it has looked more like ministers hoovering up powers they don’t know how to use and sidelining any practices that inconvenienced them. Either way, Conservatives have put surprisingly little thought into the consequence of this unshackled state falling into the hands of their opponents. A Labour Party that is inimical to much of what the Tories hold dear is on course for a parliamentary majority in a system where the institutional and cultural checks on executive power have been weakened.

Sir Keir Starmer, Labour’s leader, is an institutionalist, who loathed Boris Johnson’s disregard for norms and promises to put officials back on their pedestals. Yet he is also an instrumentalist, who has employed every clause of the Labour rulebook and every chapter of parliamentary procedure to bring his party to the brink of power. He wants to do things by the book, but the book is also there to be used. Sir Keir thinks the state is siloed and drifting; he wants to get it moving to revive the economy and restore public services. As his chief of staff, he has hired Sue Gray, a former mandarin who is temperamentally averse to constraining Whitehall.

In the government’s hands a statement of the constitutionally obvious—that Parliament is sovereign to legislate as it wishes—has been used as a pretext to do whatever is politically convenient. Should Labour secure a large majority, as its poll lead suggests it might, that stance will look less smart. Sir Keir’s office has vetted its candidates far more rigorously than Sir Tony Blair’s did before his landslide win in 1997, so that they can be relied on to pass his legislative programme. Sir Keir does not have much appetite to end the Commons’ dominance: a proposal for an elected second chamber, which would act as a stronger check than the House of Lords, has been kicked into the long grass.

Not that MPs will always be needed to get things done. Sir Keir told business leaders recently that he would crack on with planning reform without legislation: “I don’t want to get bogged down. We’ve got to get on with it from day one.” Handily, over the past decade the statute book has been laced with powers that allow ministers to devise regulatory codes or amend existing legislation with little parliamentary oversight. Take the Retained EU Law Act, which allows sweeping amendments to old EU law on the strikingly broad grounds of  “changes in technology” or “developments in scientific understanding”. Rishi Sunak, the prime minister, warns that Angela Rayner, the deputy Labour leader, wants to heap red tape on enterprise; doing so has never been easier.

Free-market Eurosceptics have little to show for breaking off the EU’s legal girdle. But Brexit has enabled Sir Keir to make one of his most popular policy proposals: levying sales tax on private schools, which many Tories regard as vandalism and which was impossible under the bloc’s tax rules. If Rachel Reeves, the shadow chancellor, can find the money for her dirigiste vision, she will have greater freedom to spend it; that is because Mr Johnson loosened the old EU subsidy-control rules, which had been pushed for by Margaret Thatcher to make Europe more competitive (Some on the Conservative right also now question the wisdom of a new ministerial definition of “extremist”, since Labour’s idea of “extreme” may differ from their own.)

When a government has a strong majority and interventionist instincts, the courts become a more important check. But the senior judiciary has given the executive more leeway since clashes between the government and the Supreme Court during the years of Brexit fighting. Analysis by Lewis Graham of the University of Oxford finds that the Supreme Court has ruled in favour of public bodies more often since the presidency of Lord Reed began in 2020. Sir Keir will further this trend: he promises to trim the grounds for time-sapping judicial reviews that hold up big infrastructure projects. Rural Tory MPs who like executive power in theory will not welcome this.

Now I am become death, destroyer of the green belt 

The Tories tend to rediscover the case for limited government in opposition. Indeed, a Labour government can produce hysterics. Winston Churchill claimed that Clement Attlee, his wartime coalition partner, would create a Gestapo. The tenure of James Callaghan, the mild-mannered head of a weak government, prompted Lord Hailsham to declare that British democracy was nothing more than an “elective dictatorship”, checked only by the consciences of its members and Commons procedure.

The principal check on the Tory government has been its own dysfunction: it has been too divided to put the powers it accumulated to effective use. For a new Labour government, the main restraint would be ministers’ willingness not to abuse the system they inherit. But these are politicians, not monks. At the end of the film, Oppenheimer is asked when he got moral qualms about his project. “When it became clear to me that we would tend to use any weapon we had.” In politics, as in physics, self-restraint is rarely enough. A spell in opposition may remind the Tories of that. ■