On this same point, the exclusionary nature of party primaries - from a party that crowns themselves the tolerant party - doesn't help.The problem is that they have spent so many years living as "ANY criticism of a black person* NO MATTER HOW LEGITIMATE makes you a racist" that they are tongue-tied. It was to Biden's CREDIT that he could straddle the line and say, "Reform the police, don't defund the police" and win with people who aren't insane.
I'm always amused at the fact the average liberal Democrat can name Willie Horton but can't name the mentally lobotomized black man that Bill Clinton signed the warrant for his execution (that was carried out) on Friday and then appeared with his wife on "60 Minutes" after the Super Bowl on Sunday. (Methinks if Clinton was a Republican, we'd know that name quite well).
It is the UNWILLINGNESS to engage in nuance that hurts candidates. If one of them would go Full Seth Moulton and just say, "Nobody is checking genitals at the bathroom, but I draw the line at boys now girls competing in sports," they'd be shocked at how many people agree with them and would actually vote for them even if they disagreed with them on some issues.
1) Don't pretend when Republicans hand your behind to you that they somehow had ideas the voters liked.
"I think it is fair to say that the Republicans were the party of ideas for a pretty long chunk of time there the last 10 or 15 years in the sense that they were challenging conventional wisdom."
Hillary tried to hang Obama for saying what was, in fact, happening in the 80s. It doesn't matter whether one likes it or not. See, he's not permitted to admit the Dems might have been on the short end somewhere.
2) Don't acknowledge being in the Senate means working with people whom you loathe.
It would be different if Biden would have said, "I signed off on Jim Crow laws in order to get health care passed," but the fact is, a lot of people in DC have bad ideas (some things we think are mainstream now will forever tag people 50 years from now as having been "wrong").
Nobody is saying "hey, it's great Stennis was a racist." But you still have to work with those you loathe.