Then, at a brokered convention, they'll be able to better justify why they're giving the nod to Biden as their pick to run for president. They'll have to tread very carefully. Trump is going to be saying how Bernie's getting screwed to aggravate his supporters so they don;t come out to vote for Biden. Obama will of course come out at the convention to rally them to support Biden, which I suspect most will do in the end, or stay home. It's a risky strategy for them. But the alternative is probably a loss against Trump or if Bernie actually won, he wouldn;t owe them anything any more than Trump owed the republican party after his one-hand win.