[Ed. – This means you, Hillary.]
The weakness of solid liberals is that they are electorally nothing, absent alliances with less affluent, less ideologically rigid, and less secular groups. This creates all kinds of complications. The largely white and affluent solid liberals are notionally egalitarian and opposed to white privilege, but they include many of the most privileged whites in America. How can they participate in a coalition that is largely poorer, less educated, and darker-skinned than they are, while maintaining their comfortable position (both economically and socially)?
One solution would be for them not to maintain their privileged position, but instead to prioritize the interests of the poorer, less secular, and more moderate parts of their coalition. But that hasn’t happened so far. An overwhelming majority of Hispanics opposes increasing immigration, but their position is entirely unrepresented in the Democratic party. It seems possible that the Democrats will throw away a winnable Senate seat in Alabama because they have nominated a pro-abortion extremist against a Republican who has been credibly accused of sexual assault and ephebophilia (probably better that you don’t look that up).