Biden’s team rejected warnings from fellow Democrats that he was a weak candidate for 2024 by constantly noting that he had been underestimated by others in the party during the 2020 primaries. That’s silly. Elections are hard to predict; conditions change; Biden’s aides weren’t geniuses in 2020, nor were they total fools in 2024. But in a party where power and authority are given to those who claim they are election soothsayers, the safest course is to never endorse anyone in an election so you will never look stupid. That’s what many Democratic groups and politicians did in 2020 nationally and in California this year.

Third, as political scientists Daniel Schlozman and Sam Rosenfeld argue in a recent book, the Democratic Party (and in many ways the GOP, as well) is “hollow,” without a strong structure. The California Democratic Party, like most state parties today, has very little power. The Democratic National Committee is fairly weak too. The real power is with prominent politicians like Harris, Pelosi, Obama, and Newsom, as well as left-leaning unions and groups. But Newsom and Harris probably don’t think of themselves as party leaders whose job it is to shape primaries by encouraging some candidates and discouraging others. They didn’t seek that role. They may not want it. In reality, though, unless the most famous politicians in the party endorse candidates, primaries turn into protracted contests like in California this year.

There’s an alternative to this scattershot approach to primaries: what Mamdani and Trump are doing. Yes, those two don’t seem much alike. But in this one way, they’re similar. Trump has a clear sense of the kinds of Republicans he wants in office. He endorses his favorites in primaries and accepts that sometimes his candidates lose, without being gun-shy about making future endorsements.