Yet anxiety about the Trump administration seems to be making Democrats more cautious and less radical. Progressives “have misread the mood,” Wason Center political scientist Rachel Bitecofer told me. “The current mood of the Democratic electorate is ‘terrified.’ When people are terrified, they seek safety and become risk-averse.”

Bitecofer warned progressives not to view the relative success of Sanders’ 2016 primary campaign as a harbinger for 2020. “Turnout in 2016 for the Democratic primary was low because Democrats were unmotivated and uninterested after eight fat and happy years not having their sensibilities attacked during the Obama years,” she said. “Many simply assumed Obama would be replaced by eight years of Hillary. As such, the 2016 electorate was slightly more ideological than I expect the 2020 electorate to be. I am expecting extremely high turnout in this primary. That increase will come primarily from moderates and liberals, not from the progressive base.” Bitecofer defines “progressive” as further to the left than “liberal.”

Five months ago, when Al Gore’s former running mate, Joe Lieberman, said he didn’t believe Rep. Ocasio-Cortez would be the future of the Democratic Party, she memorably shot back, “New party, who dis?” After the Biden surge, progressives should be less sure that they own the party.