Because he's been inarticulate and shown a hazy memory in Senate confirmation hearings, one needs to reach beyond the man's words.
Jefferson Beauregard Sessions III knows that users vote Democrat and if you felonize them, they can't.
Do you need any more subtle explanation, when that one suffices?
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Ancillary, cumulative, and congruent facts; here, here, here and in fairness, here. But again, the simplest explanation suffices nicely. Per Occam's Razor. That said, why not ice the cake?