Most of the party’s presidential candidates took the claims of the ascendant left at face value when they undertook their campaigns. Candidates like Harris, Booker, O’Rourke, and Elizabeth Warren designed their platforms as if they had to compete ideologically with Sanders. Several of them have already advocated Medicare for All or the Green New Deal, which could expose them to withering attacks from Trump if they win the nomination. Harris told an interviewer that, yes, she would do away with private health insurance. Julián Castro endorsed cash-payment reparations. Warren and Kirsten Gillibrand called for abolishing ICE, before backing off and saying they only wanted to reform it.

None of these plans stands a chance to pass Congress under the next president, even in the best-case scenario. All of them poll badly. (Medicare for All sounds popular until you tell people it means eliminating private insurance, at which point it grows unpopular.) The candidates seem to have overestimated how much left-wing policy voters actually demand. Democratic voters might be dissuaded from nominating their former vice-president if they hear more about his long record or if he repeats the undisciplined campaigning that led to defeats in both of his previous presidential campaigns. But it is already clear enough that he is supplying something much closer to what the party’s electorate wants than either the political media or the other candidates had assumed. A Democratic Party in which Biden is running away with a nomination simply cannot be the one that most people thought existed. Some of Harris’s advisers, the Times recently reported, are urging her to stop mollifying activists and embrace her prosecutorial past.

It might slowly be dawning on the left that its giddy predictions of ascendancy have not yet materialized. Corey Robin, a left-wing writer who has previously heralded the left’s impending takeover of the Democratic Party, recently conceded he may have miscalculated.