Harris' best chance..

Most optimistic case for Harris: she shores up the Black, Hispanic, and young voter blocs that Biden was lagging in this cycle and holds the other coalitions.

The latter could be done through abortion and January 6th/Project 2025 messaging. These things turn off voters (even some Republicans) broadly across all demographics. It is why Trump completely ignored them during the Republican convention.

This could open up the Sunbelt again if it occurred.

It will be interesting to see the polling post nomination.