One eye symbolism again.
Yes, POTUS is very smart. He loves America and the people. He wouldn't just let it end like this.
The way each ballot is printed, the offset margins, even text spacing could be used to stored digital data specific to the voter.
Microdots could be used. I'm sure there are smaller microdots than we officially know. Mil tech could have it.
Isotopes in paper or ink - possibly or vary the conductivity of the ink per ballot to give it a unique signature.
Watermarks
Special paper with encoded nanofibres.
To store a single 4 byte integer would require only 4 Bytes which is 32 bits of data.
You could offset the text on each line left or right by 0.01mm to carry that data.
WWG1WGA