But for Bernie, the definition of a “rigged system” has always been whatever suits his self-interest. The only constant is the fixed identity of the victim: him.

If the past is prologue, Bernie will cry foul all the way to Milwaukee. Should he lose—whether at the ballot box (more likely) or on the convention floor (less likely)—we can expect his assertion of situational victimhood to evoke a Pavlovian response: A recent survey showed that almost half his supporters might defect should the Democrats nominate anyone else; 16 percent of them promised that they would.

Biden will no doubt do all he can to convince Sanders voters to support him in November, spelling out policies which address their most urgent concerns. But for that recalcitrant 16 percent, one fears that this isn’t about policy. It’s about purity- and entitlement.