Hillary Clinton won around 55% of the popular vote in last year’s Democratic primary; Bernie Sanders, a grumpy socialist from Vermont who is not even a Democrat, took 43%. Among voters under 30, however, Mr Sanders crushed her, winning just over 2m votes: more than Mrs Clinton and Donald Trump combined. The man knows his base: today he releases “The Bernie Sanders Guide to Political Revolution”, a young-adult version of his bestselling tub-thumper, “Our Revolution”. Is the new book meant to keep his voters from 2016 politically engaged as Mr Sanders steps gracefully aside, or is it an appeal to those who will vote for the first time in 2020? Though Mr Sanders will be 79 in 2020, he has spent the past year acting like a candidate preparing to run again, rather than a grandfather about to retire: staging campaign-style events around America. Elizabeth Warren (among others) appears ready to seize the party’s progressive mantle, but Mr Sanders may not be ready to let it go just yet.