one non-technological defence against fraud is having the elections conducted in a decentralised way. This is already implemented in the US as each of the indiv

one non-technological defence against fraud is having the elections conducted in a decentralised way. This is already implemented in the US as each of the individual states have responsibility. This doesn't defend against potential fraud by individual voters but it does offer some defence against potential fraud at a national level by the federal government -- the system would arguably be a lot more vulnerable if a single coherent government bureaucracy ran the election.