Excellent question. Unfortunately even Falwell can't talk sense into every one who calls themselves a Christian.
---45% of Catholics and 39% of “Protestant/Other-denomination” Christians voted Democrat in the 2016 Presidential Elections,
according to Pew. In other words, Christians have the power to swing the 2020 election---
townhall.com
No Christians vote Democrat.
“Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only the one who does the will of my Father who is in heaven.
22Many will say to me on that day, ‘Lord, Lord, did we not prophesy in your name and in your name drive out demons and in your name perform many miracles?’
23Then I will tell them plainly, ‘I never knew you. Away from me, you evildoers!’