In her speech to the Labour Party conference in Liverpool on October 9th, Rachel Reeves, the shadow chancellor, promised economic stability after “the wreckage of Tory misrule”. But she was curiously silent about the overall stance of fiscal policy, the lever that is most directly under the control of the chancellor.

A few of the Labour Party’s preferred villains—such as private schools, large tech firms and energy companies—would pay a bit more tax if Ms Reeves were to move into 11 Downing Street after the next election. A few pet schemes would receive more government cash. But the overall shape of public spending and taxation, at least on day-to-day spending, would be remarkably similar to that planned by the current Conservative chancellor, Jeremy Hunt. In her speech Ms Reeves pledged “iron discipline” on public spending overall. In doing so, Ms Reeves is bearing out a political theory associated with one of Labour’s particular bêtes noires: George Osborne, the Tory chancellor between 2010 and 2016.

Long before he was chancellor Mr Osborne had worked as a political strategist. One lesson he drew then from the Conservative defeats of 2001 and 2005 was the “baseline theory of politics”. The medium-term fiscal plans set out in the government’s budget are often notional—economic circumstances change, after all. But the media and voters would nonetheless treat these numbers, Mr Osborne believed, as the baseline, or common-sense starting-point, for any discussion of tax and spending. Any proposed deviation from that baseline, warranted or not, would be subject to heavy scrutiny.

In those 2001 and 2005 election campaigns, for example, Conservatives had found themselves being pushed to identify exactly which public services would be cut in order to fund their planned tax reductions. In the 1992 election campaign, Labour’s plans for higher public spending had been presented as a “tax bombshell”; five years later Sir Tony Blair’s incoming Labour government stuck to the baseline and simply pledged to match Conservative spending plans.

As chancellor, Mr Osborne was able to put his baseline theory into practice. In the 2015 election, the Conservatives committed themselves to £40bn (then worth $61.2bn), or 2% of GDP, of post-election spending reductions. When Labour failed to match this commitment, Mr Osborne argued that a Labour government would lead to more taxes and more borrowing. But soon after winning the 2015 election, the Tories put together another budget and softened their plans for public-spending cuts. The old baseline had served its purpose; a new one could be adopted. This might have been smart politics, according to former officials, but it was bad policymaking.

The current government may now be attempting something similar. A quirk of the timing around how Britain sets out public-spending plans occasionally gives the chancellor of the day more political wriggle-room. British budgets set out the total pot allocated for departmental spending, capital spending and other types of spending for the current fiscal year and the four subsequent ones. The spending review divides up this total spending between actual departments, but it does not last as long. In the autumn statement next month, Mr Hunt will set out the government’s fiscal plans until 2027-28. But the current spending review runs until only 2024-25, and the government has no plans to update it this side of a general election.

This is the moment one former budgetary official calls “the danger period”, when the current government can set the baseline ahead of an election without specifying where cuts will actually fall. If it wins, the government can change the numbers soon afterwards; if it loses it will be someone else’s problem to solve. And in the meantime, it can paint any deviation by Labour from its plans as a fiscal black hole.

Even without such political gameplaying, Ms Reeves would have limited room for manoeuvre. Labour typically has to work harder than the Tories to persuade voters that it can be trusted with the economy. And money is tight: government debt is close to 100% of GDP; interest rates have risen, leading to higher debt-servicing costs. But her decision to keep largely to the fiscal path set by the Tories is also because of the baseline theory of politics and the shadow of Mr Osborne. ■