Which leads to the third point: Progressives may not like Biden all that much, but they should do more than hold their noses and vote for him — they should work vigorously for his victory. That should be obvious, given the massive and justified discontent with President Trump.

But voters of a certain generation will never forget how discontented progressives in 2000 fled the Democratic Party and its nominee, Al Gore — an unexciting, imperfect moderate — to vote for Ralph Nader, thus helping George W. Bush narrowly win the presidency. And it has been only four years since some supporters of Sen. Bernie Sanders (I-Vt.) revolted against Hillary Clinton’s nomination — though Sanders himself campaigned respectably for her that fall.

There is still time for this year’s progressives to campaign for Sanders or Sen. Elizabeth Warren (D-Mass.), of course. But if Biden does win the nomination, there will be no time for petulant, third-party rebellion. Trump is that bad. Biden might not offer the agenda aggressiveness the party’s left-wing desires, but this shouldn’t be a close call. A Bidenesque half-loaf is far superior to the dystopian nothing Trump has to offer them.