Ask 1930’s Germany.

Problem is, they don't need to cull the complete half.

And

They are taking bites out of whatever's left of a fair election process in the USA, all over the place. The threat of actual physical violence, as horrifying as that is, is unfortunately only one of many efforts.

Let's look at the other times this has happened historically

For voting blue? No. For being antifa terrorist sympathizers? Probably.

They'll try.