struth.
When Mr. Biden withdrew, it was only months before National Democratic Convention. Individual state parties did not have the time necessary to convene another primary in all 50-States.
It takes a least to plan for such primary. I know from my own experience as Delegate the State Democratic Convention the time takes one to plan that convention. The machinations needed for a primary are many and each state party would have fund the new primary. There was no time for such a vast undertaking.
The Executive Committee of Democratic Nation Committee (State Party Chairs and Deputy Chairs And National Chairman) and Deputy Chairs held a meeting and agreed to a "
Mini-Convention" (allowed under the rules of D.N.C.) of state delegates. The delegates voted and elected to make VP Kamala Harris the party nominee. All legal and above board. FYI, if Diaper Don had dropped dead from Big Mac Diet, the R.N.C. would done the exact same exact ******* thing.