This is, once again, for the umpteenth time, the Bigfoot argument.
Nobody can say with absolute certainty that Bigfoot doesn't exist, and it's the same wrt voter fraud. All kinds of elaborate excuses & scenarios can be fabricated in support of the hypothesis that it does in meaningful measure, and the side effects of that, & of trying to stop Bigfoot are thrown to the wind, because we must stop voter fraud & Bigfoot!
The sad truth is that the side effect, disenfranchisement, is the desired result, because those promoting the conspiracy theory know that voter fraud is every bit as much a chimera as Bigfoot... and have said as much many times.
It's all part & parcel of the notion that there is no sin when you have God on your side, that the ends justify the means.
If Righties are so sure that their ideas will prevail at the polls & in the "marketplace of ideas" that they tout so highly, why do they want to keep people from participating?
Because they care not for democracy in the slightest, other than as a fig leaf, a claim to legitimacy as hollow as their ideology-
http://www.youtube.com/watch?v=8GBAsFwPglw