Trump appealed to working class voters here in a rather unique way. Biden was essentially the same type of candidate that Hillary was, so he wasn't able to make significant headway among Obama-Trump voters. It remains to be seen whether WC voters will stick with the next Republican presidential nominee not named Trump, but for now, I think Democrats need to win statewide by at least 15 points in order to win this county.
I doubt 15% is needed statewide in a presidential election. If a Democrat could win by five or six, I guess that would be enough. But that statewide margin is a tall order.
