Why would the election be null and void? I’d think a farmer could run without support from a political party and if he won wouldn’t the election count?
Short answer: Because the people refuse to vote the way the Establishment wants.
I expect the next step will have Republicans and Democrats work together to defraud all elections nationwide.
They probably can’t make the election null and void after the fact. But they can publicize that those wanting to vote for Moore would be wasting it in an attempt to try and suppress the vote.