Rigging elections is so easy because there are so many options available. You can use electronic voting machines that can be easily hacked, hide numerous ballots in the trunks of cars, or just redraw voting districts in the most cockamamy way possible to ensure people who support your party outnumber those who support the other party.
Minnesota’s districts are up for redrawing and has already been turning into quite the controversy. The Republicans want to redraw the districts so that the Republican Party is favored while the Democrats want to redraw the districts to that the Democrat Party is favored. Do you know what common goal the Republicans and Democrats share? Power. Neither part gives two shits about you, your rights, or ensuring fair elections are held.