The continuing uncertainty in the Democratic presidential primary has a hole the size of Barack Obama at its center.
One reason the race remains so unsettled is that none of the contenders has reassembled the winning coalition of groups that Obama coalesced during his 2008 run to the nomination, a model that Hillary Clinton largely followed to capture the prize in 2016.
Instead, only two months before the first voting begins in Iowa, the principal components of the Democratic coalition are fragmenting, with such key demographic groups as whites with and without college degrees, African Americans and Hispanics all tilting toward different contenders. CONT.
Ronald Brownstein, CNN