President Joe Biden bids farewell to his party Monday night. And whatever he says, he will get a rousing reception for one simple and deeply unusual reason: He’s no longer Democrats’ standard-bearer, and they are relieved he saw the political writing on the wall and passed the baton to someone who might have a better chance to defeat former President Donald Trump.

Despite the cheers, let’s not pretend this isn’t an awkward and bittersweet moment for Biden. I’ve spent my entire…