The Atlantic has an article arguing that the mostly white electorates in Iowa and New Hampshire are the reason there are no non-whites in the small group of Democrats still considered serious contenders for the nomination. Hat tip to RealClearPolitics for the link.
I’d argue this hypothesis is false. If Harris, Booker, or Castro had great national poll numbers their lackluster polls in IA and NH wouldn’t matter. Note for example that former VP Joe Biden - given little chance of a first place showing in either IA or NH - is still considered a front runner for the nomination.
The truth is none of these three - Harris, Booker, Castro - electrified the nation’s black and Hispanic communities, if polls are to be believed. Alternatively, maybe communities of color are less excited about electing another of their own following Obama’s less-than-brilliant performance in office.