After months of mostly pointless speculation (including by yours truly), Joe Biden announced on Tuesday that Kamala Harris would be the Democratic nominee for vice president in the 2020 presidential election.

No presumptive nominee from either of our two major political parties has waited this long to announce his running mate in the modern primary era. These decisions are usually made in July or earlier. The question is why it took so long here. It is hard to imagine that the lockdowns played any role except insofar as they have allowed Biden to run what is in virtually every sense the strangest presidential campaign of modern times. Instead I think it is more likely that Biden came to regret his spur-of-the-moment declaration that he would select a woman for the number-two spot and has spent the last several months despairing of the choices available to him.

Whom might he have selected, though, if it had not been for this self-imposed constraint? It seems to me supremely unlikely in the current political climate that he would have chosen an older white man. On paper Cory Booker remains the ablest and most interesting of the younger Democratic senators, but there was something mysteriously lacking in him for which I have still not seen an adequate explanation. Julian Castro, very briefly a media darling, was unsparing in his criticism of Biden during last year's debates and did not endorse the former vice president until two months ago, on June 2. Pete Buttigieg would have been an unthinkable choice for the older African-American voters who continue to be the most reliable portion of the Democratic electorate even if he and Biden had not exchanged some of the vicious attack ads of the primary cycle.

In fact, the willingness of virtually all the viable candidates for the nomination to go after Biden, and their collective inability to damage him in the eyes of Democratic primary voters, is one of the most remarkable features of this race. If Biden had limited himself to people who had not said anything nasty about him during the preceding twelve months, his choices would have been limited to John Delaney (remember him?) and, well, Tim Kaine.

This is why I do not think we should make too much of the contentious exchanges during the primary between Biden and Harris on busing and race relations. Politicians rarely mean any of the things they say, and given the choice between running alongside someone she all but dismissed as an out-of-touch septuagenarian racist last fall and staying where she is, it would unthinkable for someone with her obvious ambition to decline this chance.

So much for why it was plausible. The question now is why Harris' selection was considered desirable. The most obvious reason is that she was in a very real sense the preferred candidate of the Democratic establishment, someone many of us thought had the best shot at winning the party's nomination in 2020. Harris is the perfect embodiment of the centrist Democratic establishment, a politician with equivocal views on crime and drugs but rock-solid pro-abortion credentials, undeniably woke but totally uninterested in the progressive economic policies. Harris is by nature a cop, like Hillary Clinton. She is also someone Democratic leaders would be comfortable seeing in the Oval Office herself, which was the single most important question involved in selecting a running mate for a candidate who would be the oldest president in American history on his first day in office.

Harris' selection will probably not have much of an effect on the outcome of the race in November. If there are any remaining undecided voters, they are suspending their judgement for other reasons. She will not bring disaffected progressives back into the fold, but neither would any candidate Biden would have considered selecting. Instead, what Harris represents is what the Democratic Party sees as its future: the lite-libertarianism of centrist economics, open borders, and social liberalism.

Sounds familiar.