While Sanders’s fellow candidates didn’t parrot his vocabulary and denounce “oligarchs” and “oligarchy,” they spoke expansively about gross income inequality and the need to tackle it. That largely reflected how wealth had been concentrated over recent decades. But it owed something, too, to Sanders’s right and righteous demand that America have this conversation.

Biden’s proposed tax increases of about $3.4 trillion over a decade are more than double what Clinton was advocating in 2016, while Buttigieg’s were more than quadruple. How is that moderate?

The scare that Sanders put into Clinton four years ago and the organization that he built have transformed the party, moving it even further left than the questionable electoral successes of his movement justify. Although there is scant evidence in recent elections that a Democrat running on Sanders’s platform can win anywhere but in decidedly blue districts and states, that platform colored the Democratic primary in a bold and indelible way. Candidates disrespected it at their peril.

As the Democratic race narrowed to about half a dozen plausible contenders, Klobuchar asserted herself — and was frequently characterized as — a sort of common-sense centrist. But her actual positions and proposals told a different story. As my fellow Times Op-Ed columnist David Leonhardt recently wrote: “She wants to raise taxes on the rich, break up monopolies, vastly expand Medicare, fight climate change, admit more refugees, allow undocumented immigrants to become citizens, ban assault weapons and require universal background checks. A Klobuchar administration would probably be well to the left of the Obama administration.” It would be closer to Sanders territory.

“All the lead contenders are running on the most progressive agendas to ever dominate a Democratic primary,” wrote Vox’s Ezra Klein and Roge Karma late last year. They noted that this primary’s moderates would have been considered leftists in the recent past. “As a result,” they added, “if Biden or Buttigieg actually win the nomination, they will be running on the most progressive platform of any Democratic nominee in history.”

Buttigieg was designated a moderate despite his support for abolishing the Electoral College and expanding the Supreme Court, both of which would be profound changes in American politics and governance.

Biden was designated a moderate despite declaring that the Equality Act, which would offer sweeping federal protection against discrimination for L.G.B.T.Q. people, didn’t merely have his support; it would be his top legislative priority. He was designated a moderate despite being among the 10 candidates at a Democratic debate early on who all raised their hands when asked if they supported extending health care benefits to undocumented immigrants.