But none of this made the slightest difference in the outcome. Or, put another way, none of it did Mrs. May any good. In the early stages of the campaign, some of her supporters privately admitted that she had called this snap election for fear that Labour would ditch Mr. Corbyn later in the year and deprive the Conservative Party of an opportunity for a landslide victory.

Mrs. May took that shot, and missed by miles. Her decision to cling to power now looks undignified; that is out of character. Moreover, her alliance with the unionists looks like an act of desperation. It is.

From 2010 to 2015, the Conservatives (then led by David Cameron) governed in coalition with the Liberal Democrats under Nick Clegg (who lost his seat in this election). That alliance, long-planned and carefully choreographed, was hard enough to maintain, even with plenty of common ground between the center-right Tories and their center-left partners.

The Democratic Unionist Party, in contrast, is a hard-line reactionary party, devoted not only to the union of Britain and Northern Ireland, but to a social conservatism that directly contradicts the modernization of the Conservative Party in the past 15 years. When she was the party chairman from 2002 to 2003, Mrs. May did much to brush away the cobwebs, daring to tell annual conference delegates that theirs was perceived as “the nasty party.” Now, nearly 15 years later, she has allied it with the Even Nastier Party.

How will she explain to the socially liberal, centrist voters whom Mr. Cameron won over during his decade-long leadership that she must now govern in partnership with a group of homophobes, zealots and creationists?

Mrs. May might claim that it is her duty to form a government, given the alternative: some improbable Corbyn-led rump of Labour plus the Liberal Democrats and the various nationalists. But that alone is not sufficient justification for this shabby deal, which will only confirm the suspicion that all the Conservatives truly care about is power.

Worse, Mrs. May has failed to acknowledge the scale of what has happened, or even that it has happened at all. Whatever one thinks of Mr. Corbyn’s credentials and record, he tapped into a popular anger and a yearning for change, as the Brexiteers and Mr. Trump did. He understood how to achieve emotional resonance and, most impressively, inspired young people to vote.