Election Systems and Software has long maintained that there is absolutely no way that any of their voting systems can be accessed remotely.
Apparently they have now had to admit they were lying.
(Read it and weep ...)
It's dangerous and unreliable, but, what the heck, lets do it anyway ...
What needs to be remembered is context.
For 8 years I served on my local district's election board. Our polling machines were made in the early 2000's, with a mechanical touch panel and LEDs which showed which candidate was chosen on the ballot that was affixed over the panel. Inside the locked cabinet there is a data cartridge that recorded the votes, and a paper tape that printed the vote totals. The back of the cabinet has LED counters and other diagnostic indicators.
I could not tell you how many people believed these devices could be hacked into from either across town or overseas, despite these devices having no data connectivity.
Now I am not saying there aren't polling devices that are connected; I am simply saying that not all are online. If states/local jurisdictions called up an accredited cyber security engineer (like, I don't know, maybe a CISSP?) who can examine the polling devices and determine whether or not they are online that might go a long way in dispelling the idea the devices can be hacked.
Of course, what the humans who tabulate the data do after the polls are closed are another story entirely.
Grandpa Rob @rslade has provided a series of news articles from enterprises like BBC, VICE, and New York Times.
For a more appropriate and relevant report suitable for our infosec community, see
National Academies of Sciences, Engineering, and Medicine. 2018. Securing the Vote: Protecting American Democracy. Washington, DC: The National Academies Press. https://doi.org/10.17226/25120.
As it happens, the latest RISKS-Forum Digest (sent September 28, 2018) has a number of pieces related to voting systems and other election risks ...
And another couple: