With the doctrinaire blockheads on the left this most certainly will not compute. To them, life is like a Disney movie where the bad guys are the bad guys - no nuance, no acceptable alternative perspective.
Their whole worldview crumbles into the fever swamp of their minds if they allow their brains to engage.
This is why the argument should be in the simplest terms for them. If we stick to this being just a Demorat/republican issue, they may understand it.
The perception that republicans were the slaveholders and segregationists is growing. To evoke the true history of what was the Party of slaves and segregation can be done by just a hyperbolic slogan - BAN THE DEMORAT PARTY !!!