> they would have to have all new primaries <
If Biden withdraws from the race, I think his delegates would become free agents at the convention. And then the convention will pick the nominee, as was done in the old days before primaries.
But suppose Biden refuses to withdraw? The DNC could change the rules and make his delegates free agents on the first round of voting. That could deny Biden the nomination, but only if enough of Biden’s delegates are willing to vote for someone else.
As you noted, the Democrats are in a mess of their own making.
Biden would have to get 25th amendment, no way in hell will he do that..his family doesn’t want him to quit cause he needs to pardon his son, especially now that we find out that Hunter has been in highly classified intel meetings, that alone is grounds for impeachment, he never had security clearance
“The DNC could change the rules and make his delegates free agents on the first round of voting.”
Correct.
Rules come first, then voting for candidates.