Instead of looking for ways to bring them into the tent, the Dems have to make a firm decision to write off the Know-Nothing 27% of the electorate (writing off the 3% greedpig plutocrats and their donations will be harder for them, but it’s still doable). No more pandering to delusions about supernatural forces, no more pandering to Joe-Duh-Plumber* delusions that everyone can be a $250-thousandaire under a neoliberal system, no more attempts to make appeals to “hard-working Americans…white Americans” who are deluded that their skin colour makes them superior beings.
That still leaves the Dems with a very large number of conservative-leaning voters who can be reasoned with, but candidates for federal office have to actually campaign in the swing states. Not doing so leads to disaster, as we saw in November of 2016.
[* disclaimer: Joe was not his real name, and he was an unlicensed plumber]