The current system favors the reproduction of people with at least enough intelligence to vote but maximally stupid otherwise
The people who run the system then create policies to favor faster reproduction rates for stupider people
Having faster reproduction rates for stupider people enables there to continue to be people who vote for the hand picked candidates promoted by the mainstream media outlets run by people in charge
No amount of voter fraud prevention can fix the problem of the media
Regardless of actual election outcome the people who control the media have the power to change the published voting results to be different than the results counted in the local election districts if they so choose
If a discrepancy occured & if someone found such a difference it might persuade some people but the majority would believe the results published by the mainstream media instead of those counted in the district by vote regulation officials as long as stupid people reproduce faster
The reproduction of stupid people is not only a matter of genetic selection but of cultural selection
You could have a pair of genetic identical twins each adopted by a different family and neither raised by their biological family and deoending on the sorrounding culture one twin might be stupider than the other
Those in charge would set policies to favor the biological reproduction and also the ability to adopt children for the stupider twin rather than the smarter twin to maintain power