If the ballots were marked with a specific isotope by Homeland Security for example, or a series of specific isotopes, would not those isotopes all have a very specific signature ?
Something to do with differences in neutron number, and consequently in nucleon number
All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom….
So it would be a matter of checking each ballot for the correct isotopic signature, to weed out the forged ballot papers…
Just thinking out loud…..