They cheated their usual amount in 2016 and it wasn’t enough.
They did not make that mistake in 2018, they ramped up the fraud and even flipped House seats AFTER election day.
They flipped those house seats post Election Day by changing the rules and catches the R complacent in taking advantage of the rule change... and those flips were almost all in cali. Which will never vote GOP so again, no threat to a presidential election.