So, this article claims that Google search rankings can have a a profund impact on voter choice. Bigger than anything seen elsewhere.
Let's start by looking up Robert Epstein. Is he well-regarded in this field?
We scan the blurb of this Wikipedia page and it seems to be the same person -- a psychologist and journalist.
His qualifications look good. This is a legitimate expert.
We do notice this section on his work on Google, let's check it out.
We do see his work in this area is controversial,and has been criticized for lack of transparecy and small sample size. Others have pointed out his work postulates direct intentional manipulation, but that there is no evidence of any manipulation of that sort.
So where does this leave us? It's an interesting study if if can be replicated transparently, and maybe at a larger scale. But if we want to use this citation to support an argument, we would have to dig much deeper into this. There are enough questions around this that it would need further vetting.