Next year will be pivotal in British politics, and 7 May will be the point around which things pivot. Elections to local councils, the Scottish parliament and the Welsh Senedd will give millions of voters across the UK a chance to express party preferences. Their verdicts could imperil Labour and Conservative leaders. In Wales, Labour might be sent into opposition for the first time since devolution. Plaid Cymru and Reform UK are set to make substantial gains. At Holyrood, the Scottish National party (SNP) is on course for a majority. That would be an extraordinary defiance of political gravity for a party weighed down by nearly two decades of incumbency.

In England, both Labour and the Tories risk losing scores of councillors as their vote shares are gobbled up by the Liberal Democrats, Reform UK and the Greens. Those results will be taken as evidence that Sir Keir Starmer and Kemi Badenoch are failing as leaders. But it would be a mistake to filter the results only through that lens. The fragmentation of national allegiances began much longer ago.

While electorates have routinely used midterm ballots to punish the party in government, devolution changes the calculus of power. The SNP has shrewdly presented itself as a champion of resistance to remote rulers in Westminster, deflecting accountability for its own record in government. In Wales, Labour benefited from a similar dynamic when Downing Street was in Tory hands. That trick is no longer available. The Conservative threat has receded.

© The Guardian