Well, kabud, what I can tell you about elections here stems only from my experience in Ohio. The principal safeguards are four:
1) Requirement for a secondary ID number and a signature for matching on every official document: registration, requests for mail-in ballot, mail-in ballots, paper ballots at the polls, or access to voting machines.
2) Protocols that require at least two citizen volunteer pollworkers, one from each party–and sometimes all six pollworkers at once, three from each party–for every action from opening the polls, unsealing the machines, processing the voters, managing the machines, certifying the counts against the fresh signatures on the voting rolls, resealing the machines, and closing the polls.
3) State law mandated County Board of Election protocols for unsealing the machines, and counting the votes.
4) Ohio Department of State supervision of (3) backed up by powers of arrest of the Ohio Highway Patrol; and legal recourse through the courts if (3) and/or (4) break down.
In my experience, (1) and (2) make it extremely difficult for any single fraudulent voter to actually obtain a ballot, or access to a voting machine. Also, (4) is very difficult to subvert because the state supervisors do not actually handle the ballots or counts.
This leaves (3) as the weakest link in the chain. To that all I can say is that anybody fiddling with things at the Board of Election level risks not only being fired, but also being prosecuted, as would anyone trying to bribe them.
When all four of these things are done properly, voting fraud on any scale large enough to spike an election is far too difficult and dangerous to be worth trying. The system is not foolproof against a single fraudulent voter [I think none can be] but fraud on any scale is effectively held in check.
But, beyond that, all we can do is step up, become involved as citizens of a free country, and demand that these four things are done right.
