Why can’t a simple fingerprint scanner be used at the polls?

My dude, all you really need are people who want free and fair democracy. America as a whole, doesn’t.

This is why you gerrymander, hang your chads, restrict based on ID, use easily compromized voting machines, have judges determine elections, reduce polling stations in blue areas and make long line ups with no time off work and an endless line of similar fuckery.

America is not a democracy. There is no technical trick that can fix bad faith actors.