What has happened fairly decisively at the close of the 2010s is that the combination of vanishing Labour heritage in the postindustrial areas and a feeling of anger about socio-economic marginalization have dovetailed to finally sever the bonds between the party and its traditional base. The sorts of seats that the Conservatives won from Labour last Thursday — like Bolsover in the North Midlands and Bishop Auckland in the North East — have been slipping steadily away from Labour in successive elections since the Blairite period. At the end of the 2010s, they simply fell off a cliff.

There is a sense in which the Labour Party’s rediscovery of its radical roots following Jeremy Corbyn’s election as its leader in 2015 arrived too little and too late to check these long-term processes of fraction and disillusion. Under Mr. Corbyn, Labour developed an economic and social program that would have begun the revival of its heartlands — with concrete proposals for reinvestment in community infrastructure and workers’ rights. And in the 2017 election, though the North East swung ominously toward the Conservatives, the party mostly managed to arrest the slow decline of its support.

No such stemming was achieved this year. Many of the party’s ideas, which were not cogently communicated to the electorate in the party’s overelaborate 2019 manifesto, remained abstract promises. And two and a half years of parliamentary impasse hardened attitudes about Brexit, while Labour’s vacillating stance on the issue pleased no one.

Perhaps more to the point, Labour under Mr. Corbyn failed to develop a really assertive, popular strategy for reviving the postindustrial regions it took for granted for too long. For the Conservatives, an opportunistic appeal to pro-Brexit sentiment — voters seem to have rallied behind Mr. Johnson’s “Get Brexit Done” slogan — and disenchantment with Labour were enough to conquer the Red Wall.

There are obvious limits to what Labour — as a party locked in opposition, most likely for the next five years — can plausibly do to re-empower and re-engage with the territories it presided over for the long 20th century. Nevertheless, it must now develop a compelling offer. Making the case assertively for devolution of power to the English regions and the relocation of major institutions outside of London could be a start.

It will be difficult, but the party must try. If it does not, it will not only remain on the political margins for far longer than five years. It will also have said goodbye once and for all to the better side of its own history.

Alex Niven (@Alex_Niven) is a lecturer at Newcastle University in England and the author, most recently, of “New Model Island: How to Build a Radical Culture Beyond the Idea of England.”

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