Voter fraud is not currently much of a problem, because solid-red and solid-blue states don't have much incentive to allow it (since the ruling party is already confident of its majority), and swing states don't want to risk encouraging it in case the other side gets into power and uses it against them.

Once there is even a suggestion that some state might be increasing its power by encouraging voter fraud, there will be an arms race of other states trying to "counteract" this by encouraging their own voter fraud.