Earlier quoted context omitted.
I'd rather say it's a good idea but it also is a technical problem that is not yet convincingly solved. It is clear though that open source by itself is not a solution, for the very reason you mention (how can one be sure about what code is running on a machine one doesn't own?). That being said, from times to times articles show up about someone who claimed to have invented a viable solution. So we should not diss t…
pvote.org seems like a decent solution, it's That doesn't handle auditing the machines themselves, but as the 2016 US presidential election recount found in Wisconsin, the tamper-evident machines showed evidence of tampering, so maybe we're closer to knowing whether the trusted systems we use to count votes are trustworthy. Of course, the current machines are still Diebold ("Premier Election Solutions"), so who knows…
"Pvote is small. The current version is 460 lines of Python. It uses Pygame for graphics and audio."
So, add to that 130000 lines of pygame, 1.5 million lines of cpython, 14 million lines for gcc, 20 million for the linux kernel, ... and you haven't even begun to list all the stuff you would need to audit?