When facts are in short supply, I say go with common sense.
(1) Why would millions of illegal immigrants in California and New York deliberately commit a federal felony when almost all the Democrats they vote for can be elected without any voter fraud at all?
(2) In Texas and Florida, why have no Republican candidates claimed they lost their elections because of illegal immigrant voter fraud?
There are no plausible answers for either of those questions.
Ask B1 Bomber Bob that question. They would have absolutely no support in pursuing that line.