How did this old iberal “stop” him from voting? Not clear on that.
I was a volunteer at my polling place one year. I think we did receive some pay but it wasn't much.
My role was to look up the person's name on a list of registered voters to verify that they were registered. Most voters offered their drivers license to establish identity though I don't think that was required. I live in a rural area and it's perhaps not surprising that many voters were known to one or more poll workers.
If the person's name was on my list, then I drew a line through their name on the printout and the worker next to me handed them a ballot. As I recall, another worker would then access a second list of voters attached to a bulletin board at the entrance to the polling place and cross off the same name. In that way we maintained two separate lists of who had voted and who had not.
To answer your simple question, then, a poll worker could refuse to recognize the name on the list or could refuse to hand them a ballot. We did have a "supervisor" but none of the rest of us would have allowed for a situation to get out of hand like the one described in the posted article. When it comes to affecting a person's vote, it's critical to make the right decision and there are resources available to make sure the decision is right. One can always issue a "provisional ballot" which is segregated from the rest and which can be fully accepted at a later time when all the facts and the applicable law are determined.