The great philosopher and parliamentarian Edmund Burke was the first to notice, before it even happened, that the initially peaceful protests of the French Revolution would turn into a purge of moderates by violent radicals. Something like that seems to be happening to American liberals today.

Prime example: the Bennet brothers, Sen. Michael Bennet of Colorado and former New York Times editorial page editor James Bennet, who have been having a bad year. I’ve known them only slightly but admired them as thoughtful and serious liberals, the kind of people that Democratic politicians and Democratic journalists might look to for leadership. But very few have been doing that in 2020.