Sure with gerrymandering. I’ve been involved in two major elections in the last 12 months in the uk, one as a candidate. I couldn’t think of any way of significantly changing the votes without another party finding out. Can’t register fake people in bulk, can’t registrr normally non voting people for postal votes without them finding out, can’t vote as multiple people without a lot of co conspirators and without at least some finding out they’d already voted, can’t introduce fake ballots without many conspirators, can’t change ballots or lose ballots