To argue that Sanders has qualities in common with Reagan is not to argue that he’s necessarily the most electable Democrat, or that in nominating him the party wouldn’t be taking a substantial risk — as Reagan really was a risky choice in 1980, and his victory by no means foreordained.

But it is to argue that if you want a new president to be transformative — as, obviously, many people on the left desire — there are clear advantages in electing somebody whose entire career is associated with an ideological insurgency, and whose victory would shock the more adaptable sort of politician into understanding themselves as inhabitants of a new political reality, in which no matter what poll numbers show on any given issue, it’s taken for granted that the former world has passed away.