elections are as fraud save as they are because you have humans in the loop. Hundreds of them, all over the place. And it is not judgement, but decentralized supervision that solves this problem for you. Not some flimsy electronic system without auditable paper trail.
Hundreds of humans who can all work for a single individual or organization. Without any additional rules, adding more people to supervise is simply security theater.
Note, I am not a general proponent of electronic voting machines either. They can easily make fraud easier by reducing the number of people to bribe to the few engineers with access to the blackbox code and the few officials who certify that the code is valid and was used on Election Day.